A multi-channel reverse-jet swirl single-cone burner and its use method

Abstract

The present invention relates to a multi-channel reverse jet swirl single cone burner and a method for using the same, the burner comprising a coal powder supply mechanism, a transition channel, a multi-stage air distribution component, a guide plate, a combustion stabilization chamber and a rectifier chamber; the multi-stage air distribution component comprises N air guide tubes, the Nth air guide tube is sequentially connected with the combustion stabilization chamber and the rectifier chamber to form a burner body, the coal powder supply mechanism runs through the inside of the burner body, and the transition channel is sleeved on the coal powder supply mechanism; except for the Nth air guide tube, the remaining air guide tubes are double-layer hollow structures, and one end of at least one guide plate is inserted into the corresponding air guide tube; at least one direct current channel is formed between each guide plate and the combustion stabilization chamber, and a flared port is formed at the other end of each guide plate, and the flared port has the same angle as the combustion stabilization chamber. Due to the design of the multi-stage air distribution component, the present invention is divided into N streams to enter the burner body, the turbulence intensity at the airflow boundary is strong, and the air-powder mixing rate is enhanced, which not only makes the coal powder stably ignite, but also ensures the high-efficiency and low-nitrogen combustion of the coal powder.

Description

Technical Field

[0001] The invention relates to a pulverized coal burner, in particular to a multi-channel reverse-jet swirl single-cone 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, the load adjustment range of pulverized coal burners is narrow and the adaptability of coal types is poor; and compared with chain furnaces and circulating fluidized beds, pulverized coal industrial boilers still have the problem of high nitrogen oxides. Summary of the invention

[0003] In response to the above problems, one of the objects of the present invention is to provide a multi-channel reverse-jet swirl single-cone burner with extremely wide load regulation range, strong adaptability to coal types and low nitrogen characteristics; another object of the present invention is to provide a method for using the multi-channel reverse-jet swirl single-cone burner.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a multi-channel reverse-jet swirl single-cone burner, comprising a coal powder supply mechanism, a transition channel, a multi-stage air distribution component, a guide plate, a stable combustion chamber and a rectifying chamber; the multi-stage air distribution component comprises N air guide cylinders coaxially arranged from the inside to the outside, and N is a natural number not less than 2; wherein the Nth air guide cylinder is sequentially connected with the stable combustion chamber and the rectifying chamber to form a burner body, the coal powder supply mechanism runs through the inside of the burner body, the transition channel is sleeved on the coal powder supply mechanism, and the first air guide cylinder is sleeved on the outside of the transition channel at intervals, so that there is a gap between the adjacent two air guide cylinders. And a total of N air inlet channels are formed between the first air guide tube and the transition channel; at the same time, except for the Nth air guide tube, the remaining air guide tubes are all double-layer hollow structures, that is, the inner side of each of the remaining air guide tubes is provided with an annular groove extending along the axial direction, and one end of at least one guide plate is inserted into the annular groove of the corresponding air guide tube to be fixed thereto; thereby, at least one direct current channel is formed between each of the guide plates and the combustion stabilization chamber, and a flared opening is formed at the other end of each of the guide plates, and the angle of the flared opening is the same as that of the combustion stabilization chamber, so that the outlet end direction of the direct current channel is parallel to the wall surface of the combustion stabilization chamber.

[0005] The multi-channel reverse-jet swirl single-cone burner preferably has N air inlet channels with different radial widths, so that corresponding air guide tubes can be selected and inserted into the guide plate according to different coal types and loads.

[0006] For the multi-channel reverse-jet swirl single-cone burner, preferably, the number of the guide plates is controlled between 1 and 4, and when there are more than two guide plates, the length of the guide plate located on the inner side should be smaller than the length of the guide plate located on the outer side.

[0007] The multi-channel reverse-jet swirl single-cone burner preferably has the coal powder supply mechanism mainly composed of an air-powder pipe and a reflux cap, the air-powder pipe is placed on the central axis of the burner body, and the reflux cap is arranged at the outlet end of the air-powder pipe and located at the outlet section of the stable combustion chamber.

[0008] The multi-channel reverse-jet swirl single-cone burner preferably has a transition channel that is a cylindrical structure with one end open and the other end closed, and the air-powder tube passes through the closed end of the transition channel and extends into the interior of the burner body, and an igniter and / or flame detector is installed in the transition channel.

[0009] The multi-channel reverse-jet swirl single-cone burner preferably has a transition channel that 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 first air guide tube, and the narrowest diameter should be larger than the maximum diameter of the igniter and / or flame detector.

[0010] A method for using the above-mentioned multi-channel reverse-jet swirl single-cone burner comprises the following steps:

[0011] 1) According to the type of coal, select the appropriate length and number of guide plates and insert them into the corresponding air guide tubes, and note that the position of the innermost guide plate is the mth air guide tube, and install axial impellers along the circumferential direction in the 1st to mth air inlet channels;

[0012] 2) The air is divided into N streams by the graded air distribution assembly and enters the burner body, among which the 1st to mth streams of air pass through the axial impeller to form mth rotating air beams with tangential velocity and enter the stable combustion chamber, and the mth rotating air beams interact with each other to form a multi-layer nested high-temperature reflow zone;

[0013] 3) At the same time, the coal powder airflow enters the high-temperature reflow zone through the reflow channel composed of the air-powder pipe and the reflow cap. The coal powder presents a concentration distribution of thick outside and thin inside. The coal powder is preheated to 900-1000℃ in the high-temperature reflow zone. The coal powder is pyrolyzed in the low-oxygen and hot high-temperature reflow zone, and mixed with multiple rotating air beams under the joint action of the transition channel to form a multi-layer main flame;

[0014] 4) The m+1~Nth air inlet channels form DC channels. The m+1~Nth air flows form DC wind beams with different speeds after passing through the DC channels. The DC wind beams have two functions: the first function is to form a cooling air layer flowing along the wall of the stable combustion chamber after the expansion of the guide plate to cool the stable combustion chamber and the rectifying chamber; the second function is to form a high-speed jet multi-layer flame with wind-wrapped fire with the main flame through the rectifying chamber and enter the furnace.

[0015] 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 length of the guide plate is lengthened and / or the number of the guide plates is increased; if the coal is of low volatile matter and low calorific value, the length of the guide plate is shortened and / or the number of the guide plates is reduced.

[0016] In the method of use, preferably, the swirl number of the rotating wind beam generated by the axial impeller should be controlled in the range of 0.6 to 2.

[0017] In the method of use, preferably, the wind speed of the DC wind beam should be controlled within the range of 30 to 50 m / s.

[0018] Due to the adoption of the above technical scheme, the present invention has the following advantages: 1. The present invention adopts the design of a multi-stage air distribution component. The air is divided into N streams through the multi-stage air distribution component and enters the burner body. The turbulence intensity at the airflow boundary is strong, which enhances the air-powder mixing rate, not only making the coal powder stably ignite, but also ensuring the efficient and low-nitrogen combustion of the coal powder. 2. The multi-stage air distribution component of the present invention is composed of a plurality of air guide tubes coaxially arranged from the inside to the outside, and the air guide tube adopts a double-layer hollow structure. The guide plate can be inserted into the double-layer hollow structure of any air guide tube, thereby forming a multi-layer flame structure with cooling wind attached to the wall of the stable combustion cavity and the rectifying cavity. The combustion-supporting wind slowly penetrates into the main flame, ensuring that the middle of the main flame is a high-temperature, high-CO and low-oxygen environment, prolonging the residence time of the coal powder in the high-temperature, reducing atmosphere, and achieving the purpose of high combustion efficiency and low nitrogen. At the same time, the DC wind beam formed between the guide plate and the stable combustion chamber can form a cooling air layer flowing along the wall of the stable combustion chamber in 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 can not only eliminate the water cooling device of the stable combustion chamber, but also avoid the occurrence of ash coking on the wall of the stable combustion chamber. 3. The present invention can mechanically control the mixing rate of the combustion-supporting air and the main flame by adjusting the length and number of the guide plate, and the load adjustment range is 10% to 110%, which has an extremely wide load adjustment range. In addition, it has the characteristics of wide adaptability to coal types, good stable combustion and low nitrogen. 4. The present invention also adopts a transition channel design, 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 of the built-in movable axial impeller to produce a reflux zone with high turbulence intensity, enhance the mixing rate of coal powder and air, and improve the burnout rate of coal powder under low load conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the three-dimensional longitudinal section structure of the multi-channel reverse-injection swirl single-cone burner of the present invention;

[0020] Figure 2 It is a schematic diagram of the two-dimensional longitudinal section structure of the multi-channel reverse-injection swirl single-cone burner of the present invention;

[0021] Figure 3 It is a schematic diagram of the internal flow field of the multi-channel reverse-jet swirl single-cone burner of the present invention. DETAILED DESCRIPTION

[0022] 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.

[0023] 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.

[0024] like Figure 1 , Figure 2As shown, the multi-channel reverse-jet swirl single-cone burner provided by the present invention comprises a pulverized coal supply mechanism 1, a transition channel 2, a multi-stage air distribution assembly 3, a guide plate 4, a combustion stabilization chamber 5 and a rectification chamber 6. The multi-stage air distribution assembly 3 comprises N air guide cylinders (N is a natural number not less than 2) coaxially arranged from the inside to the outside, wherein the Nth (i.e., the outermost) air guide cylinder is sequentially connected with the combustion stabilization chamber 5 and the rectification chamber 6 to form a burner body, the pulverized coal supply mechanism 1 runs through the inside of the burner body, the transition channel 2 is sleeved outside the inlet end of the pulverized coal supply mechanism 1, and the first (i.e., the innermost) air guide cylinder is sleeved outside the transition channel 2 at intervals, thereby forming a total of N air inlet channels between two adjacent air guide cylinders and between the first air guide cylinder and the transition channel 2. At the same time, except for the Nth air guide tube, the remaining air guide tubes are double-layer hollow structures, that is, the inner side of each of the remaining air guide tubes is provided with an annular groove extending along the axial direction, and one end of at least one guide plate 4 can be inserted into the annular groove of the corresponding air guide tube to be fixed thereto. Thus, at least one direct current channel is formed between each guide plate 4 and the combustion stabilization chamber 5, and the other end of each guide plate 4 is formed with a flared opening, the flared opening having the same angle as the combustion stabilization chamber 5, so that the outlet end direction of the direct current channel is parallel to the wall surface of the combustion stabilization chamber 5.

[0025] In the above embodiment, preferably, the radial widths of the N air inlet channels are different, so that the corresponding air guide tubes can be selected to be inserted into the guide plate 4 according to different coal types and loads, thereby controlling the mixing rate of air and the main flame, adjusting the high-temperature recirculation zone, and thus broadening the load adjustment range of the burner and the adaptability of the coal types.

[0026] In the above embodiment, preferably, the number of guide plates 4 is controlled between 1 and 4, and when there are more than two guide plates 4, the length of the guide plate 4 located on the inner side should be smaller than the length of the guide plate 4 located on the outer side.

[0027] In the above embodiment, preferably, the pulverized coal supply mechanism 1 is mainly composed of an air-powder pipe 11 and a reflux cap 12. The air-powder pipe 11 is placed on the central axis of the burner body, and the reflux cap 12 is arranged at the outlet end of the air-powder pipe 11 and located at the outlet section of the stable combustion chamber 5.

[0028] In the above embodiment, preferably, the transition channel 2 is a cylindrical structure with one end open and the other end closed, and the air powder tube 11 passes through the closed end of the transition channel 2 and extends into the interior of the burner body. An igniter and / or a flame detector (not shown in the figure) can be installed in the transition channel 2.

[0029] 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 first air guide tube, and the narrowest diameter should be larger than the maximum diameter of the igniter and / or flame detector.

[0030] like Figure 3As shown, based on the multi-channel reverse-jet swirl single-cone burner provided in the above embodiment, the present invention also proposes a method for using the multi-channel reverse-jet swirl single-cone burner, comprising the following steps:

[0031] 1) According to the type of coal, the guide plates 4 of appropriate length and quantity are selected and inserted into the corresponding air guide tubes, and the position of the innermost guide plate 4 is recorded as the mth air guide tube, and axial impellers (not shown in the figure) are installed circumferentially in the 1st to mth air inlet channels;

[0032] 2) The air is divided into N streams by the graded air distribution component 3 and enters the burner body, wherein the first to m streams of air pass through the axial impeller to form m rotating air beams with tangential velocity and enter the stable combustion chamber 5, and the m rotating air beams interact with each other to form a multi-layer nested high-temperature reflow zone;

[0033] 3) At the same time, the coal powder airflow enters the high-temperature recirculation zone through the recirculation channel composed of the air-powder pipe 11 and the recirculation cap 12. The coal powder presents a concentration distribution of thick outside and thin inside. The coal powder is preheated to 900-1000°C in the high-temperature recirculation zone. The coal powder is pyrolyzed in the low-oxygen and hot high-temperature recirculation zone and mixed with multiple rotating air beams under the joint action of the transition channel 2 to form a multi-layer main flame.

[0034] 4) The m+1~Nth air inlet channels form DC channels. The m+1~Nth air flows form DC wind beams with different speeds after passing through the DC channels (the wind speed decreases from the outside to the inside). The DC wind beams have two functions: the first function is to form a cooling air layer flowing along the wall of the stable combustion chamber 5 after the expansion of the guide plate 4, 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; the second function is to form a high-speed jet multi-layer flame of wind-wrapped fire with the main flame through the rectifying chamber 6 and enter 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.

[0035] In the above embodiment, preferably, in the above step 1), if the coal is high in volatility and calorific value, the length of the guide plate 4 can be lengthened and / or the number of the guide plates 4 can be increased, thereby delaying the time for the combustion-supporting air (including the rotating air beam and the direct current air beam) to mix with the main flame, so that the reducing atmosphere in the main flame is enhanced, which is beneficial to reducing nitrogen oxides; if the coal is low in volatility and calorific value, the length of the guide plate 4 can be shortened and / or the number of the guide plates 4 can be reduced (even the guide plates 4 can be eliminated), thereby strengthening the mixing of the combustion-supporting air and the main flame, which is beneficial to the ignition of the coal powder and the stable combustion of the coal powder. It can be seen that by adjusting the length and number of the guide plates 4, the mixing rate of air and the main flame can be mechanically controlled, and the load adjustment range can reach 10% to 110%.

[0036] In the above embodiment, preferably, the swirl number of the rotating wind beam generated by the axial impeller should be controlled within the range of 0.6 to 2.

[0037] In the above embodiment, preferably, the wind speed of the DC wind beam should be controlled within the range of 30 to 50 m / s.

[0038] 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 multi-channel reverse jet swirl single cone burner, characterized in that: It comprises a pulverized coal supply mechanism (1), a transition channel (2), a multi-stage air distribution component (3), a guide plate (4), a combustion stabilization chamber (5) and a rectifying chamber (6); The multi-stage air distribution component (3) comprises N air guide tubes coaxially arranged from the inside to the outside, and N is a natural number not less than 2; wherein the Nth air guide tube is sequentially connected with the combustion stabilization chamber (5) and the rectifying chamber (6) to form a burner body, the coal powder supply mechanism (1) runs through the inside of the burner body, the transition channel (2) is sleeved on the coal powder supply mechanism (1), and the first air guide tube is sleeved on the outside of the transition channel (2) at intervals, thereby forming a total of N air inlet channels between two adjacent air guide tubes and between the first air guide tube and the transition channel (2); At the same time, except for the Nth air guide tube, the remaining air guide tubes are all double-layer hollow structures, that is, the inner side of each of the remaining air guide tubes is provided with an annular groove extending along the axial direction, and one end of at least one of the guide plates (4) is inserted into the annular groove of the corresponding air guide tube to be fixed thereto; Thus, at least one direct current channel is formed between each of the guide plates (4) and the combustion stabilization chamber (5), and a flared opening is formed at the other end of each of the guide plates (4), wherein the angle of the flared opening is the same as the angle of the combustion stabilization chamber (5), so that the outlet end direction of the direct current channel is parallel to the wall surface of the combustion stabilization chamber (5).

2. The multi-channel reverse-jet swirl single-cone burner according to claim 1, characterized in that: The radial widths of the N air inlet passages are different, so that corresponding air guide tubes are selected and inserted into the guide plate (4) according to different coal types and loads.

3. The multi-channel reverse-jet swirl single-cone burner according to claim 1, characterized in that: The number of the guide plates (4) is controlled to be between 1 and 4, and when there are more than two guide plates (4), the length of the guide plate (4) located on the inner side should be smaller than the length of the guide plate (4) located on the outer side.

4. The multi-channel reverse-jet swirl single-cone burner according to claim 1, characterized in that: The pulverized coal supply mechanism (1) is mainly composed of an air-powder pipe (11) and a return cap (12); the air-powder pipe (11) is placed on the central axis of the burner body; the return cap (12) is arranged at the outlet end of the air-powder pipe (11) and is located at the outlet section of the combustion stabilization chamber (5).

5. The multi-channel reverse-jet swirl single-cone burner according to claim 4, 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) passes through the closed end of the transition channel (2) and then extends into the interior of the burner body. An igniter and / or a flame detector is installed in the transition channel (2).

6. The multi-channel reverse-jet swirl single-cone burner according to claim 5, characterized in that: 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 first air guide tube, and the narrowest diameter should be larger than the maximum diameter of the igniter and / or flame detector.

7. A method for using the multi-channel reverse jet swirl single cone burner according to any one of claims 4 to 6, characterized in that: The following steps are involved: 1) According to the type of coal, a guide plate (4) of suitable length and quantity is selected and inserted into the corresponding air guide tube, and the position of the innermost guide plate (4) is recorded as the mth air guide tube, and an axial impeller is installed along the circumferential direction in the 1st to mth air inlet channels; 2) The air is divided into N streams by the graded air distribution component (3) and enters the burner body, wherein the first to m streams of air pass through the axial impeller to form m rotating air beams with tangential velocities and enter the stable combustion chamber (5), and the m rotating air beams interact with each other to form a multi-layer nested high-temperature reflow zone; 3) At the same time, the coal powder airflow enters the high-temperature recirculation zone through the recirculation channel formed by the air-powder pipe (11) and the recirculation cap (12). The coal powder presents a concentration distribution of thick outside and thin inside. The coal powder is preheated to 900-1000° C. in the high-temperature recirculation zone. The coal powder is pyrolyzed in the low-oxygen and hot high-temperature recirculation zone and is mixed with multiple rotating air beams under the joint action of the transition channel (2) to form a multi-layer main flame. 4) The m+1 to Nth air inlet channels form direct current channels. After passing through the direct current channels, the m+1 to Nth air streams form direct current air beams with different speeds. The direct current air beams have two functions: the first function is to form a cooling air layer flowing along the wall of the stable combustion chamber (5) after the expansion of the guide plate (4) to cool the stable combustion chamber (5) and the rectifying chamber (6); the second function is to form a high-speed jet multi-layer flame with wind enveloping the main flame through the rectifying chamber (6) and enter the furnace.

8. The method of use according to claim 7, characterized in that: In the above step 1), if the coal has high volatile matter and high calorific value, the length of the guide plate (4) is lengthened and / or the number of the guide plates (4) is increased; If the coal is of low volatile matter and low calorific value, the length of the guide plate (4) is shortened and / or the number of the guide plates (4) is reduced.

9. The method of use according to claim 7, characterized in that: The swirl number of the rotating wind beam generated by the axial impeller should be controlled in the range of 0.6 to 2.

10. The method of use according to claim 7, characterized in that: The wind speed of the DC wind beam should be controlled within the range of 30 to 50 m / s.

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