A dual-channel thick-lean separation burner and its use method

Abstract

The present invention relates to a dual-channel thick-thin separation burner and a method for using the same. The burner includes a coal powder supply mechanism, a transition channel, an inner / outer secondary air guide, a combustion stabilization chamber and a rectifying chamber; the outer secondary air guide, the combustion stabilization chamber and the rectifying chamber are connected in sequence, the coal powder supply mechanism includes an air-powder pipe and a thick-thin separator, the air-powder pipe is connected to the combustion stabilization chamber, and the thick-thin separator is detachably connected to the air-powder pipe; the inner secondary air guide is coaxially spaced in the outer secondary air guide, and the transition channel is coaxially spaced in the inner secondary air guide; the outlet end of the inner secondary air guide is formed with a flared opening, and the flared opening angle is the same as the angle of the combustion stabilization chamber. The present invention can separate air into inner and outer secondary air and enter the burner respectively, the inner secondary air is combined with the transition channel to fully mix the coal powder and air, and the outer secondary air can form a cooling air layer flowing along the wall of the combustion stabilization chamber in the combustion stabilization chamber to avoid the occurrence of ash and coking on the wall of the combustion stabilization chamber.

Description

Technical Field

[0001] The invention relates to a pulverized coal burner, in particular to a dual-channel thick-thin separation type burner and a use method thereof, belonging to the technical field of efficient and clean utilization of coal. Background Art

[0002] At present, in the field of pulverized coal industrial boilers, there are many types of burners such as blunt body burners, swirl burners and reverse jet burners. Their common point is to use the high-temperature recirculation zone as the ignition source to ignite the pulverized coal airflow to achieve the purpose of high-efficiency and low-nitrogen combustion of pulverized coal. However, due to the intense combustion of pulverized coal inside the burner, the temperature inside the burner can reach above 1100°C, and the burner is in the high-temperature combustion zone for a long time, so there is a phenomenon of high-temperature thermal corrosion; and compared with chain furnaces and circulating fluidized beds, pulverized coal industrial boilers have a narrow load adjustment range and are prone to low burnout rate during low-load operation. Summary of the invention

[0003] In view of the above problems, one of the objects of the present invention is to provide a dual-channel rich-lean separation burner with the characteristics of wide load regulation range, stable combustion and low nitrogen; another object of the present invention is to provide a method for using the dual-channel rich-lean separation burner.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a dual-channel thick-lean separation burner, comprising a coal powder supply mechanism, a transition channel, an inner secondary air guide tube, an outer secondary air guide tube, a stable combustion chamber and a rectifying chamber; wherein, the outer secondary air guide tube, the stable combustion chamber and the rectifying chamber are connected in sequence to form a burner body, the coal powder supply mechanism comprises an air-powder pipe and a thick-lean separator, the air-powder pipe is arranged on the central axis of the burner body and is connected to the stable combustion chamber, the thick-lean separator is detachably connected to the air-powder pipe, and is used to make the coal powder fed into the stable combustion chamber thick inside and thin outside. Or a concentration distribution that is light inside and thick outside; the inner secondary air guide tube is coaxially spaced inside the outer secondary air guide tube to form an outer secondary air channel between the inner secondary air guide tube and the outer secondary air guide tube; the transition channel is coaxially spaced inside the inner secondary air guide tube to form an inner secondary air channel between the inner secondary air guide tube and the transition channel; at the same time, a flared opening is formed at the outlet end of the inner secondary air guide tube, and the angle of the flared opening is the same as the angle of the stable combustion chamber, thereby making the outlet end direction of the inner secondary air channel parallel to the wall surface of the stable combustion chamber.

[0005] The dual-channel thick-lean separation burner is preferably provided with a movable axial impeller assembly in the inner secondary air channel, so as to form a rotating airflow with a tangential velocity after the inner secondary air passes through the movable axial impeller assembly.

[0006] The dual-channel thick-lean separation burner preferably comprises: an axial impeller, which is circumferentially arranged in the inner secondary air channel and can move axially; an adjustable telescopic rod, one end of which is connected to the axial impeller via a first hinge pair; and a locking rod, which is connected to the other end of the adjustable telescopic rod via a second hinge pair.

[0007] In the dual-channel thick-lean separation burner, preferably, the inner secondary air guide tube and the outer secondary air guide tube are connected by a plurality of movable positioning components distributed along the circumferential direction, and the movable positioning components are used to adjust the cross-sectional area of ​​the outer secondary channel.

[0008] The dual-channel thick-lean separation burner preferably has a plurality of threaded holes opened circumferentially on the inner secondary air guide tube, a plurality of light holes opened circumferentially on the outer secondary air guide tube, and the outer secondary air guide tube has a flexible tube wall; at the same time, the movable positioning assembly is mainly composed of an adjusting bolt and a sealing gasket, and the adjusting bolt passes through the sealing gasket and the light hole of the outer secondary air guide tube and is threadedly connected with the threaded hole of the inner secondary air guide tube.

[0009] The dual-channel thick-thin separation burner preferably has a thick-thin separator that is a throat-type thick-thin separator, a gear-type thick-thin separator or a petal-shaped thick-thin separator, and an external thread is formed on the outer wall of the thick-thin separator, and an internal thread is formed on the inner wall of the outlet section of the air-powder tube. The thick-thin separator is inserted into the air-powder tube from the outlet end of the air-powder tube and is threadedly connected to the air-powder tube.

[0010] In the dual-channel thick-lean separation burner, preferably, the transition channel is a cylindrical structure with one end open and the other end closed, the air-powder tube is axially arranged in the transition channel, the outlet end of the air-powder tube passes through the closed end of the transition channel and is flush with it, and an igniter and / or flame detector is installed in the transition channel; the transition channel is a conical, elliptical or cylindrical blunt body, and the widest diameter of the transition channel should be smaller than the inner diameter of the inner secondary air guide cylinder, and the narrowest diameter should be larger than the maximum diameter of the igniter and / or flame detector.

[0011] A method for using the above-mentioned dual-channel thick-lean separation burner comprises the following steps:

[0012] 1) Select the corresponding thick-lean separator according to the type of coal and install it on the air-powder pipe;

[0013] 2) The air enters the burner body in two ways. One of the air passes through the movable axial impeller assembly and the inner secondary air channel to form a rotating inner secondary air with a tangential velocity and directly enters the stable combustion chamber. The inner secondary air channel and the transition channel work together to form a nested high-temperature reflow zone;

[0014] 3) At the same time, the coal powder airflow is injected into the stable combustion chamber through the air-powder pipe and the thick-lean separator. The coal powder presents a concentration distribution of thick inside and thin outside or thin inside and thick outside in the stable combustion chamber. The coal powder is preheated to 900-1000℃ in the high-temperature reflux zone. The coal powder is pyrolyzed in the low-oxygen and hot high-temperature reflux zone and mixed with the internal secondary air to form the main flame;

[0015] 4) Another path of the air passes through the external secondary air channel to form external secondary air. A part of the external secondary air passes through the expansion of the external secondary air guide tube to form a cooling air layer flowing along the wall of the stable combustion chamber to cool the stable combustion chamber and the rectifying chamber; the other part of the external secondary air forms a high-speed jet flame with the main flame through the rectifying chamber and enters the furnace.

[0016] The method of use is preferably such that in the above step 1), if the coal is of high volatile matter and high calorific value, the thick-thin separator is selected as a throat-type thick-thin separator or a gear-type thick-thin separator; if the coal is of low volatile matter and low calorific value, the thick-thin separator is selected as a petal-shaped thick-thin separator.

[0017] In the method of use, preferably, the swirl number of the rotating airflow generated by the movable axial impeller assembly should be controlled within the range of 0 to 2, the wind speed of the external secondary air should be controlled within the range of 20 to 50 m / s, and the ratio of the internal secondary air to the external secondary air is preferably 1:2;

[0018] In the above step 4), the cross-sectional area of ​​the outer secondary air channel is adjusted by the movable positioning assembly, thereby adjusting the wind speed of the outer secondary air and controlling the mixing rate of the inner secondary air and the outer secondary air.

[0019] Due to the above technical scheme adopted in the present invention, it has the following advantages: 1. The present invention is provided with an inner secondary air duct and an outer secondary air duct, so that the air can be divided into inner secondary air and outer secondary air and enter the burner body respectively, which not only makes the air enter the burner in stages to reduce nitrogen oxides, the inner secondary air is combined with the transition channel to make the coal powder and air fully mixed and stably burned, and the outer secondary air can form a cooling air layer in the stable combustion chamber that flows along the wall of the stable combustion chamber to cool the stable combustion chamber and the rectifying chamber, so that the wall temperature of the stable combustion chamber and the rectifying chamber is always lower than 40°C, which not only can eliminate the water cooling device of the stable combustion chamber, but also avoid the occurrence of ash and coking on the wall of the stable combustion chamber. 2. The present invention can adjust the cross-sectional area of ​​the external secondary air channel through a movable positioning component, thereby adjusting the wind speed of the external secondary air, controlling the mixing rate of the internal secondary air and the external secondary air, and thus controlling the combustion process of the coal powder airflow in the burner body, thereby forming an internal low-oxygen, high-temperature, external high-oxygen, low-temperature environment in the stable combustion chamber. This temperature distribution and atmosphere distribution can not only achieve the effect of high combustion efficiency and low nitrogen, broaden the load adjustment range and coal type adaptability of the burner, but also effectively solve the high-temperature corrosion, ash accumulation and coking of the stable combustion chamber wall, reduce the maintenance frequency of the burner, and extend the service life of the burner. 3. The present invention also adopts the design of a transition channel, which can not only have an ignition oil gun and an igniter built in, but also the transition channel can work together with the internal secondary air channel with a built-in movable axial impeller to produce a high turbulence intensity recirculation zone, enhance the mixing rate of coal powder and air, and improve the burnout rate of coal powder under low load conditions. 4. The coal powder of the present invention enters the burner through the thick-thin separator, which makes the coal powder have a concentration distribution of thick inside and thin outside. The flame is not easy to disperse, the flame rigidity is enhanced, and the flame length can be increased under the joint action of the internal and external secondary air, the stable combustion chamber and the rectifying chamber, which is helpful to improve the combustion efficiency and reduce nitrogen oxides. The present invention is suitable for the hedge arrangement and the four-corner tangential circle arrangement of multiple burners. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional longitudinal section structure schematic diagram of the dual-channel thick-lean separation burner of the present invention;

[0021] Figure 2 It is a structural schematic diagram of the movable axial impeller assembly of the present invention;

[0022] Figure 3 It is a structural schematic diagram of the movable positioning assembly of the present invention;

[0023] Figure 4 It is a schematic diagram of the structure of a throat-type thick-thin separator;

[0024] Figure 5 It is a schematic diagram of the structure of a gear-type thick-thin separator;

[0025] Figure 6It is a structural schematic diagram of a petal-shaped shade separator;

[0026] Figure 7 It is a schematic diagram of the internal flow field of the dual-channel rich-lean separation burner of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. At the same time, in the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0029] like Figure 1 As shown, the dual-channel thick-thin separation burner provided by the present invention comprises a pulverized coal supply mechanism 1, a transition channel 2, an inner secondary air guide 3, an outer secondary air guide 4, a combustion stabilizing chamber 5 and a rectifying chamber 6. Among them, the outer secondary air guide 4, the combustion stabilizing chamber 5 and the rectifying chamber 6 are sequentially connected to form a burner body, and the pulverized coal supply mechanism 1 comprises an air-powder pipe 11 and a thick-thin separator 12. The air-powder pipe 11 is arranged on the central axis of the burner body and is connected to the combustion stabilizing chamber 5. The thick-thin separator 12 is detachably connected to the air-powder pipe 11, and is used to make the pulverized coal fed into the combustion stabilizing chamber 5 present a concentration distribution of thick inside and thin outside or thin inside and thick outside. The inner secondary air guide 3 is coaxially spaced in the outer secondary air guide 4, so that an outer secondary air channel is formed between the inner secondary air guide 3 and the outer secondary air guide 4. The transition channel 2 is coaxially spaced in the inner secondary air guide 3, so that an inner secondary air channel is formed between the inner secondary air guide 3 and the transition channel 2. At the same time, a flared opening is formed at the outlet end of the inner secondary air guide tube 3 , and the angle of the flared opening is the same as that of the combustion stabilization chamber 5 , thereby making the outlet end direction of the inner secondary air channel parallel to the wall surface of the combustion stabilization chamber 5 .

[0030] In the above embodiment, preferably, Figure 2 As shown, a movable axial impeller assembly 7 is provided in the inner secondary air channel, so as to make the inner secondary air form a rotating airflow with a tangential velocity after passing through the movable axial impeller assembly 7 .

[0031] In the above embodiment, preferably, the movable axial impeller assembly 7 comprises: an axial impeller 71, which is circumferentially arranged in the inner secondary air channel and can move axially; an adjustable telescopic pull rod 72, one end of which is connected to the axial impeller 71 through a first hinge pair; and a locking pull rod 73, which is connected to the other end of the adjustable telescopic pull rod 72 through a second hinge pair. Thus, the axial impeller 71 can be moved axially to enter and exit the inner secondary air channel by pushing and pulling the locking pull rod 73, and the hinge pair can ensure smooth movement of the axial impeller 71.

[0032] In the above embodiment, preferably, Figure 3 As shown, the inner secondary air guide cylinder 3 and the outer secondary air guide cylinder 4 are connected by a plurality of movable positioning components 8 distributed along the circumferential direction, and the movable positioning components 8 are used to adjust the cross-sectional area of ​​the outer secondary channel.

[0033] In the above embodiment, preferably, a plurality of threaded holes 31 are opened on the inner secondary air guide tube 3 along the circumferential direction, a plurality of light holes 41 are opened on the outer secondary air guide tube 4 along the circumferential direction, and the outer secondary air guide tube 4 is a flexible tube wall; meanwhile, the movable positioning assembly 8 is mainly composed of an adjusting bolt 81 and a sealing gasket 82, and the adjusting bolt 81 passes through the sealing gasket 82 and the light hole 41 of the outer secondary air guide tube 4 and is threadedly connected with the threaded hole 31 of the inner secondary air guide tube 3. Thus, by screwing in or out the adjusting bolt 81, the tube wall of the outer secondary air guide tube 4 is deformed, thereby adjusting the cross-sectional area of ​​the outer secondary channel.

[0034] In the above embodiment, preferably, the thick-thin separator 12 can be a throat-type thick-thin separator (such as Figure 4 As shown), gear type thick and thin separator (as shown Figure 5 as shown) or a petal-shaped shade separator (as Figure 6 As shown in FIG. 1 , an outer thread is formed on the outer wall of the thick-thin separator 12, and an inner thread is formed on the inner wall of the outlet section of the air-powder pipe 11. The thick-thin separator 12 can be inserted into the air-powder pipe 11 from the outlet end of the air-powder pipe 11 and is threadedly connected with the air-powder pipe 11. Thus, the corresponding thick-thin separator 12 can be replaced according to the type of coal to broaden the load adjustment range and coal adaptability of the burner.

[0035] In the above embodiment, preferably, the transition channel 2 is a cylindrical structure with one end open and the other end closed, the air powder tube 11 is axially arranged in the transition channel 2, the outlet end of the air powder tube 11 passes through the closed end of the transition channel 2 and is flush with it, and an igniter and / or a flame detector (not shown in the figure) can be installed in the transition channel 2.

[0036] In the above embodiments, preferably, the transition channel 2 is conical, elliptical, cylindrical or any other curved blunt body, and the widest diameter of the transition channel 2 should be smaller than the inner diameter of the inner secondary air guide cylinder 3, and the narrowest diameter should be larger than the maximum diameter of the igniter and / or flame detector.

[0037] like Figure 7 As shown, based on the dual-channel thick-lean separation burner provided in the above embodiment, the present invention also provides a method for using the dual-channel thick-lean separation burner, comprising the following steps:

[0038] 1) Select the corresponding thick-lean separator 12 according to the type of coal and install it on the air-powder pipe 11;

[0039] 2) The air enters the burner body in two ways. One of the air passes through the movable axial impeller assembly 7 and the inner secondary air channel to form a rotating inner secondary air with a tangential velocity and directly enters the stable combustion chamber 5. The inner secondary air channel and the transition channel 2 work together to form a nested high-temperature reflow zone;

[0040] 3) At the same time, the coal powder airflow is injected into the stable combustion chamber 5 through the air-powder pipe 11 and the thick-thin separator 12. The coal powder presents a concentration distribution of thick inside and thin outside or thin inside and thick outside in the stable combustion chamber 5. The coal powder is preheated to 900-1000℃ in the high-temperature reflux zone. The coal powder is pyrolyzed in the low-oxygen and hot high-temperature reflux zone and mixed with the internal secondary air to form the main flame.

[0041] 4) Another path of the air passes through the external secondary air channel to form external secondary air. A part of the external secondary air passes through the expansion of the external secondary air guide tube 4 to form a cooling air layer flowing along the wall of the stable combustion chamber 5, so as to cool the stable combustion chamber 5 and the rectifying chamber 6, so that the wall temperature of the stable combustion chamber 5 and the rectifying chamber 6 is lower than 40°C; another part of the external secondary air forms a high-speed jet flame of wind-wrapped fire with the main flame through the rectifying chamber 6 and enters the furnace, thereby not only stably burning the coal powder, but also avoiding the occurrence of ash and coking in the burner body and the furnace.

[0042] In the above embodiment, preferably, in the above step 1), if the coal type is high in volatile matter and high in calorific value, the thick-thin separator 12 selects a throat-type thick-thin separator or a gear-type thick-thin separator, thereby producing a pulverized coal concentration distribution that is thick inside and thin outside, and the main flame rigidity is enhanced, thereby increasing the flame length of the main flame, which is beneficial to improving combustion efficiency and reducing nitrogen oxide emissions; if the coal type is low in volatile matter and low in calorific value, the thick-thin separator 12 selects a petal-shaped thick-thin separator, which can not only produce a pulverized coal concentration distribution that is thick outside and thin inside, but also form a number of small high-temperature flue gas recirculation zones near the outlet of the petal-shaped thick-thin separator, which is conducive to the ignition and stable combustion of the pulverized coal.

[0043] In the above embodiment, preferably, in the above step 2), the swirl number of the rotating airflow generated by the movable axial impeller assembly 7 should be controlled within the range of 0-2.

[0044] In the above embodiment, preferably, in the above step 4), the cross-sectional area of ​​the external secondary air channel can be adjusted by the movable positioning assembly 8, thereby adjusting the wind speed of the external secondary air, controlling the mixing rate of the internal secondary air and the external secondary air, and thus controlling the combustion process of the pulverized coal airflow in the burner body, thereby forming an internal low-oxygen, high-temperature and external high-oxygen, low-temperature environment in the stable combustion chamber 5, which not only has the effects of high efficiency and low nitrogen, but also can effectively avoid the occurrence of ash accumulation and coking in the burner body and the furnace.

[0045] In the above embodiment, preferably, the wind speed of the external secondary air should be controlled within the range of 20 to 50 m / s.

[0046] In the above embodiment, preferably, the ratio of the inner secondary air to the outer secondary air is 1:2. This ratio can not only ensure the stable combustion of the coal powder and allow the inner secondary air to mix with the main flame layer by layer to reduce nitrogen oxides, but also allow the outer secondary air attached to the wall to have sufficient momentum to cool the combustion stabilization cavity 5 and the rectification cavity 6.

[0047] In the description of the present invention, it should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the above components. Unless otherwise stated, the above terms have no special meanings and therefore cannot be understood as limiting the scope of protection of the present invention.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-channel thick-lean separation burner, characterized in that: It comprises a pulverized coal supply mechanism (1), a transition channel (2), an inner secondary air guide tube (3), an outer secondary air guide tube (4), a combustion stabilization chamber (5) and a rectification chamber (6); The outer secondary air guide tube (4), the combustion stabilizing chamber (5) and the rectifying chamber (6) are connected in sequence to form a burner body, the pulverized coal supply mechanism (1) comprises an air-powder pipe (11) and a thick-thin separator (12), the air-powder pipe (11) is arranged on the central axis of the burner body and is connected to the combustion stabilizing chamber (5), and the thick-thin separator (12) is detachably connected to the air-powder pipe (11) and is used to make the pulverized coal fed into the combustion stabilizing chamber (5) have a concentration distribution of thick inside and thin outside or thin inside and thick outside; The inner secondary air guide tube (3) is coaxially arranged at intervals inside the outer secondary air guide tube (4), so that an outer secondary air channel is formed between the inner secondary air guide tube (3) and the outer secondary air guide tube (4); the transition channel (2) is coaxially arranged at intervals inside the inner secondary air guide tube (3), so that an inner secondary air channel is formed between the inner secondary air guide tube (3) and the transition channel (2); At the same time, a flared opening is formed at the outlet end of the inner secondary air guide tube (3), and the angle of the flared opening is the same as the angle of the combustion stabilization chamber (5), thereby making the outlet end direction of the inner secondary air channel parallel to the wall surface of the combustion stabilization chamber (5); The inner secondary air guide cylinder (3) and the outer secondary air guide cylinder (4) are connected via a plurality of movable positioning components (8) distributed along the circumferential direction, wherein the movable positioning components (8) are used to adjust the cross-sectional area of ​​the outer secondary air channel; The inner secondary air guide tube (3) is provided with a plurality of threaded holes (31) along the circumferential direction, the outer secondary air guide tube (4) is provided with a plurality of light holes (41) along the circumferential direction, and the outer secondary air guide tube (4) is a flexible tube wall; At the same time, the movable positioning assembly (8) is mainly composed of an adjusting bolt (81) and a sealing gasket (82); the adjusting bolt (81) passes through the sealing gasket (82) and the light hole (41) of the outer secondary air guide tube (4) and is threadedly connected to the threaded hole (31) of the inner secondary air guide tube (3).

2. The dual-channel rich-lean separation burner according to claim 1 is characterized in that: A movable axial impeller assembly (7) is provided in the inner secondary air channel, and is used to allow the inner secondary air to pass through the movable axial impeller assembly (7) to form a rotating airflow with a tangential velocity.

3. The dual-channel rich-lean separation burner according to claim 2 is characterized in that: The movable axial impeller assembly (7) comprises: An axial impeller (71) is circumferentially arranged in the inner secondary air channel and is movable in the axial direction; An adjustable telescopic pull rod (72), one end of the adjustable telescopic pull rod (72) being connected to the axial impeller (71) via a first hinge pair; The locking pull rod (73) is connected to the other end of the adjustable telescopic pull rod (72) via a second hinge pair.

4. The dual-channel rich-lean separation burner according to any one of claims 1 to 3, characterized in that: The thick-thin separator (12) is a throat-type thick-thin separator, a gear-type thick-thin separator or a petal-shaped thick-thin separator, and an external thread is formed on the outer wall of the thick-thin separator (12), and an internal thread is formed on the inner wall located at the outlet section of the air-powder tube (11). The thick-thin separator (12) is inserted into the air-powder tube (11) from the outlet end of the air-powder tube (11) and is threadedly connected to the air-powder tube (11).

5. The dual-channel rich-lean separation burner according to claim 4 is characterized in that: The transition channel (2) is a cylindrical structure with one end open and the other end closed, the air-powder tube (11) is axially arranged in the transition channel (2), the outlet end of the air-powder tube (11) passes through the closed end of the transition channel (2) and is flush with it, and an igniter and / or a flame detector is installed in the transition channel (2); The transition channel (2) is a conical, elliptical or cylindrical blunt body, and the widest diameter of the transition channel (2) should be smaller than the inner diameter of the inner secondary air guide cylinder (3), and the narrowest diameter should be larger than the maximum diameter of the igniter and / or flame detector.

6. The method for using the dual-channel thick-lean separation burner according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) Select a corresponding thick-lean separator (12) according to the type of coal and install it on the air-powder pipe (11); 2) The air enters the burner body in two ways, one of the air passes through the movable axial impeller assembly (7) and the inner secondary air channel to form a rotating inner secondary air with a tangential velocity and directly enters the stable combustion chamber (5), and the inner secondary air channel and the transition channel (2) work together to form a nested high-temperature reflow zone; 3) At the same time, the coal powder airflow is injected into the stable combustion chamber (5) through the air-powder pipe (11) and the thick-thin separator (12). The coal powder presents a concentration distribution of thick inside and thin outside or thin inside and thick outside in the stable combustion chamber (5). The coal powder is preheated to 900-1000° C. in the high-temperature reflux zone. The coal powder is pyrolyzed in the low-oxygen and hot high-temperature reflux zone and is mixed with the internal secondary air to form a main flame. 4) Another path of the air passes through the external secondary air channel to form external secondary air. A portion of the external secondary air passes through the expansion of the external secondary air guide tube (4) to form a cooling air layer flowing along the wall of the stable combustion chamber (5) to cool the stable combustion chamber (5) and the rectifying chamber (6); another portion of the external secondary air and the main flame pass through the rectifying chamber (6) to form a high-speed jet flame with wind enveloping the fire and enter the furnace.

7. The method of use according to claim 6, characterized in that: In the above step 1), if the coal has high volatile matter and high calorific value, the thick-thin separator (12) is selected as a throat-type thick-thin separator or a gear-type thick-thin separator; if the coal has low volatile matter and low calorific value, the thick-thin separator (12) is selected as a petal-shaped thick-thin separator.

8. The method of use according to claim 6, characterized in that: The swirl number of the rotating airflow generated by the movable axial impeller assembly (7) should be controlled within the range of 0 to 2, the wind speed of the external secondary air should be controlled within the range of 20 to 50 m / s, and the ratio of the internal secondary air to the external secondary air is 1:2; In the above step 4), the cross-sectional area of ​​the outer secondary air channel is adjusted by the movable positioning component (8), thereby adjusting the wind speed of the outer secondary air and controlling the mixing rate of the inner secondary air and the outer secondary air.

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