Pulverized coal burners and combustion systems

Abstract

The present invention relates to the technical field of coal powder combustion, and in particular to a coal powder burner and a combustion system. The coal powder burner includes: a concentration device, which separates the coal powder into concentrated powder and light powder; a combustion device, which includes a cylinder and a partition, wherein the inlet of the cylinder is connected to the outlet of the flow pipe, and the partition is eccentrically arranged in the cylinder downward, and divides the internal space of the cylinder into a combustion zone and a cooling zone, wherein the combustion zone is located above the partition and is used to receive concentrated powder, and the cooling zone is located below the partition and is used to receive light powder, and the partition is retractable; and an ignition device, which includes an ignition source, and the ignition source is inserted into the combustion zone. In this way, the use flexibility of the coal powder burner can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of pulverized coal combustion, and in particular to a pulverized coal burner and a combustion system. Background Art

[0002] Pulverized coal burners have been widely used in coal-fired power station boilers. However, pulverized coal burners in the related art generally have a fixed structure, and it is difficult to achieve different combustion processes for different media or ignition conditions, and the flexibility of use is poor. Summary of the invention

[0003] A technical problem to be solved by the embodiments of the present invention is to improve the use flexibility of a pulverized coal burner.

[0004] In order to solve the above technical problems, an embodiment of the present invention provides a pulverized coal burner, comprising:

[0005] A concentrator separates the coal powder into concentrated powder and light powder;

[0006] A combustion device, comprising a cylinder and a partition, wherein the inlet of the cylinder is connected to the outlet of the flow pipe, the partition is eccentrically arranged in the cylinder downward, and divides the internal space of the cylinder into a combustion zone and a cooling zone, the combustion zone is located above the partition and is used to receive the concentrated powder, the cooling zone is located below the partition and is used to receive the light powder, and the partition is retractable; and

[0007] The ignition device includes an ignition source, which is inserted into the combustion zone.

[0008] In some embodiments, the partition is telescopic so that the length of the partition accounts for 10%-100% of the total length of the cylinder.

[0009] In some embodiments, the partition includes a first plate segment and a second plate segment, which are arranged in sequence along the flow direction of the coal powder. The first plate segment can be connected to the second plate segment by rotating up and down to change the flow area ratio of the combustion zone and the cooling zone.

[0010] In some embodiments, the first plate segment is rotated relative to the second plate segment within a range of ±30°.

[0011] In some embodiments, a mixing zone is further provided in the cylinder. The mixing zone is located downstream of the partition along the flow direction of the coal powder, and the coal powder flowing out of the combustion zone and the cooling zone is mixed in the mixing zone.

[0012] In some embodiments, the mixing zone includes a tapered section, and the flow area of ​​the tapered section gradually decreases along the flow direction of the pulverized coal.

[0013] In some embodiments, the cross section of the partition is a curved surface.

[0014] In some embodiments, the ignition device further includes a first sleeve, which is disposed in the combustion zone and sleeved on the outside of the ignition source.

[0015] In some embodiments, along the flow direction of the coal powder, the flow area of ​​the first sleeve gradually increases.

[0016] In some embodiments, the ignition device further includes a second sleeve disposed in the combustion zone, the second sleeve is sleeved outside the first sleeve, and is staggered with the first sleeve along the flow direction of the coal powder.

[0017] In some embodiments, along the flow direction of the coal powder, the flow area of ​​the second sleeve gradually increases.

[0018] The embodiment of the present invention further provides a combustion system, which includes a boiler and a pulverized coal burner according to the embodiment of the present invention, wherein the outlet of the cylinder is connected to the inside of the boiler.

[0019] By arranging a downward eccentric and retractable partition in the cylinder, the use flexibility of the pulverized coal burner can be effectively improved, and the adaptability of the pulverized coal burner to different media or different working conditions can be enhanced.

[0020] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 It is a cross-sectional schematic diagram of a pulverized coal burner in the first embodiment of the present invention.

[0023] Figure 2 It is a cross-sectional schematic diagram of a pulverized coal burner in the second embodiment of the present invention.

[0024] Figure 3 It is a cross-sectional schematic diagram of a pulverized coal burner in the third embodiment of the present invention.

[0025] Figure 4 The shapes of the partitions in some embodiments of the present invention are shown.

[0026] Description of reference numerals:

[0027] 10. Pulverized coal burner;

[0028] 1. Concentration device; 11. Elbow pipe; 14. Dense phase area; 15. Dilute phase area; 17. Flow pipe;

[0029] 2. Combustion device; 21. Cylinder; 211. First cylinder section; 212. Second cylinder section; 22. Baffle; 221. First plate section; 222. Second plate section; 23. Combustion zone; 24. Cooling zone; 25. Mixing zone; 251. Gradually contracting section;

[0030] 3. Ignition device; 31. Ignition source; 32. First sleeve; 33. Second sleeve. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without carrying out creative work are within the scope of protection of the present invention.

[0032] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0033] In the description of the present invention, it needs to be understood that, in order to facilitate the description of the present invention and simplify the description, the orientation or position relationship indicated by directional words such as "up, down, left, right, front, back", "lateral, vertical, vertical, horizontal" and "top, bottom" is usually based on the orientation or position relationship of the pulverized coal burner when it is normally placed and installed as shown in the accompanying drawings; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0034] 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 corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0035] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] Figure 1-Figure 4 The structure of the pulverized coal burner of the present invention is shown as an example.

[0037] Reference Figure 1-4 The pulverized coal burner 10 includes a concentration device 1, a combustion device 2 and an ignition device 3.

[0038] The concentrator 1 and the combustion device 2 are connected in sequence along the flow direction of the pulverized coal. The ignition device 3 is inserted into the combustion device 2. The concentrator 1 is connected to the primary air duct (not shown in the figure) and the combustion device 2, and is used to separate the pulverized coal airflow transported by the primary air duct into concentrated powder with a relatively high pulverized coal concentration and light powder with a relatively low pulverized coal concentration, and guide the concentrated powder and light powder to flow to the combustion device 2. The combustion device 2 is connected to the concentrator 1 and the boiler, and is used to receive the concentrated powder and light powder separated by the concentrator 1 for ignition by the ignition device 3. The ignition device 3 ignites the pulverized coal flowing into the combustion device 2. After the pulverized coal is ignited by the ignition device 3, it is sprayed from the outlet of the combustion device 2 into the inside of the boiler.

[0039] Separating the pulverized coal into thin and thick ones is beneficial to strengthening ignition, stabilizing combustion, and reducing NO X The flow areas of the concentrated powder and the light powder in the concentrating device 1 can be respectively referred to as the dense phase area 14 and the dilute phase area 15. That is, the concentrating device 1 has a dense phase area 14 and a dilute phase area 15, which are respectively used for the concentrated powder and the light powder to flow through.

[0040] The concentrator 1 can adopt various structural forms to achieve the separation of the coal powder into thick and thin parts.

[0041] For example, see Figure 1-3 In some embodiments, the concentrating device 1 includes a flow pipe 17. When the pulverized coal flows through the flow pipe 17, the concentrating device 1 separates the pulverized coal into concentrated pulverized coal and light pulverized coal.

[0042] Among them, see Figure 1 In some embodiments, the flow pipe 17 includes an elbow 11. When working, the elbow 11 uses centrifugal force to separate the pulverized coal into thick and thin parts. In the process of flowing through the elbow 11, the pulverized coal is separated into thick powder located on the radial outside and thin powder located on the radial inside under the action of centrifugal force, so as to achieve the thick and thin separation of the pulverized coal in the radial direction of the elbow 11. It can be understood that when the flow pipe 17 only includes the elbow 11, the inlet and outlet of the elbow 11 respectively form the inlet and outlet of the concentrating device 1, the lumen of the elbow 11 forms a concentrating zone, and the radially outer part and the radially inner part of the lumen of the elbow 11 respectively form a dense phase zone 14 and a dilute phase zone 15, so that the dense phase zone 14 is located radially outside the dilute phase zone 15, or in other words, the dense phase zone 14 is located above the dilute phase zone 15, and the dense powder and the thin powder are distributed up and down. At this time, the concentrating device 1 can be called an elbow-type concentrating device.

[0043] In addition to the elbow-type concentrator, the concentrator 1 may also adopt other structural forms such as a straight tube block-type concentrator or a shutter-type concentrator.

[0044] The combustion device 2 provides a space for the combustion of the pulverized coal. The combustion device 2 includes a cylinder 21. The cylinder 21 is hollow inside. The inlet and outlet of the cylinder 21 respectively form the inlet and outlet of the combustion device 2, and are respectively connected to the outlet of the flow pipe 17 and the inside of the boiler.

[0045] The ignition device 3 ignites the coal powder to achieve combustion of the coal powder. The ignition device 3 includes an ignition source 31. The ignition source 31 is inserted into the cylinder 21 to ignite the coal powder. The ignition source 31 can be a plasma torch, an oil gun or other ignition components in various forms.

[0046] In order to improve the performance of the pulverized coal burner 10 , the embodiment of the present invention improves the structure of the pulverized coal burner 10 .

[0047] See also Figure 1-3 In some embodiments, a partition 22 is provided in the combustion device 2. The partition 22 is provided in the cylinder 21 and extends along the length direction of the cylinder 21 (the direction from the cylinder 21 entrance to the cylinder 21 exit), and divides the internal space of the cylinder 21, so that the interior of the cylinder 21 is divided into different areas.

[0048] Specifically, Figure 1-3 As shown, in some embodiments, the partition 22 is eccentrically arranged downward in the cylinder 21, and divides the internal space of the cylinder 21 into a combustion zone 23 and a cooling zone 24. The combustion zone 23 is located above the partition 22, connected to the dense phase zone 14, and is used to receive the dense powder. The cooling zone 24 is located below the partition 22, connected to the dilute phase zone 15, and is used to receive the light powder. When the ignition source 31 is inserted into the cylinder 21, it is specifically inserted into the combustion zone 23. The ignition source 31 is not provided in the cooling zone 24.

[0049] Since the partition 22 is not centrally arranged in the cylinder 21 but eccentrically arranged, and the eccentric direction is downward, that is, the partition 22 is arranged below the longitudinal center line of the cylinder 21 (the center line from the inlet to the outlet), the eccentric direction is consistent with the direction of the light powder separated by the concentration device 1 relative to the concentrated powder, that is, the partition 22 is biased toward the side where the light powder is located relative to the cylinder 21, or, in other words, the partition 22 is biased toward the side close to the dilute phase zone 15 relative to the cylinder 21. Therefore, the flow area of ​​the combustion zone 23 for receiving concentrated powder and having an ignition source 31 inside is greater than the flow area of ​​the cooling zone 24 for receiving light powder and having no ignition source 31 inside. For example, in some embodiments, the flow area of ​​the combustion zone 23 accounts for a proportion of the total flow area of ​​the cylinder 21 that is greater than 50% and less than or equal to 90%, while the flow area of ​​the cooling zone 24 accounts for a proportion of the total flow area of ​​the cylinder 21 that is less than 50% and greater than or equal to 10%. In this way, on the one hand, the partition 22 can realize a biased concentration process together with the concentration device 1, and separate the coal powder into thin and thick ones more fully and effectively; on the other hand, when the ignition source 31 is located at the center of the combustion zone 23, the combustion center is not located at the center of the cylinder 21, but is offset, thereby realizing a biased combustion process.

[0050] In the above-mentioned biased concentration process, the concentrated powder and light powder separated by the concentration device 1 enter the combustion zone 23 and the cooling zone 24 respectively, and are separated by the partition 22. Under the further separation effect of the partition 22, the concentrated powder and light powder flowing from the concentration device 1 to the cylinder 21 will not be remixed before being ignited by the ignition source 31 and during the ignition process, thereby achieving a more reliable and more sufficient concentrated and light separation effect.

[0051] Moreover, in the above-mentioned biased combustion process, the combustion zone 23 with a larger flow area can fully receive concentrated powder, and is conducive to reducing the flow velocity of concentrated powder, so that an atmosphere with high coal powder concentration and low coal powder velocity can be formed in the combustion zone 23, which is conducive to the ignition source 31 inserted into the combustion zone 23 to ignite the concentrated powder smoothly. At the same time, the cooling zone 24 with a smaller flow area can fully receive light powder, and is conducive to increasing the light powder velocity, so that an atmosphere with low coal powder concentration and high coal powder velocity can be formed in the cooling zone 24, which is conducive to the coal powder in the cooling zone 24 where the ignition source 31 is not set to fully cool the combustion zone 23, thereby preventing coking in the combustion zone 23.

[0052] In addition, the combustion zone 23 and the cooling zone 24 separated by the partition 22 are distributed up and down, rather than other distribution relationships such as inside and outside distribution. It can be seen that the partition 22 is not a cylindrical structure, but a plate structure, which makes it possible to separate the combustion zone 23 and the cooling zone 24 without setting any inner and outer sleeve structures in the pulverized coal burner 10. At the same time, the cylinder 21 is directly connected to the flow tube 17, and the concentrated powder can smoothly enter the combustion zone 23 to form a high-concentration and low-flow coal powder airflow, without setting a transition structure between the two to guide the concentrated powder to flow to the combustion zone 23. Therefore, it is conducive to simplifying the structure of the pulverized coal burner 10. In addition, the combustion zone 23 and the cooling zone 24 are separated only by the offset partition 22, which also has the advantages of small internal resistance, strong ignition performance and anti-powder accumulation and coking ability. Because when the combustion zone 23 and the cooling zone 24 are distributed inside and outside, the internal resistance of the combustion device 2 is large, and the annular gap between the inner and outer sleeves is prone to uneven distribution of wind speed and coal powder, causing powder accumulation or burning problems. At the same time, when a transition structure is provided between the inlet of the cylinder 21 and the outlet of the flow tube 17, the internal resistance will also increase, and powder will easily accumulate at the transition structure. After the temperature rises, the accumulated powder will easily burn and burn the pulverized coal burner 10. In addition, when a transition structure is provided to guide the concentrated powder to flow to the combustion zone 23, the pulverized coal concentration at the inlet of the transition structure is high and the flow rate is fast, which will easily cause wear of the transition structure and affect the service life of the pulverized coal burner. However, the embodiment of the present invention cancels the transition structure, so that the inlet of the cylinder 21 is directly connected to the outlet of the flow tube 17, and based on the offset partition 22, a high-concentration and low-flow-rate atmosphere is formed in the combustion zone 23, which is conducive to reducing the wear of the pulverized coal burner 10 and extending the service life of the pulverized coal burner 10.

[0053] It can be seen that the interior of the cylinder 21 is divided into a combustion zone 23 with an ignition source 31 and a combustion zone 23 without an ignition source 31 by using a partition plate 22 eccentrically arranged downward, so that the pulverized coal burner 10 can perform biased concentration and biased combustion based on a simpler structure, and ignite the concentrated powder smoothly and fully without coking, thereby achieving a better combustion effect.

[0054] See also Figure 1-3 In some embodiments, the partition 22 is configured to be retractable. At this time, for the same pulverized coal burner 10, the length of its partition 22 is not fixed, but can be flexibly changed by its own extension, which is conducive to improving the flexibility of the use of the pulverized coal burner 10, so that the pulverized coal burner 10 can control the length of the partition 22 for different media or different ignition conditions. It can be understood that the length refers to the dimension along the flow direction of the pulverized coal, or in other words, the dimension along the direction from the inlet of the cylinder 21 to the outlet of the cylinder 21.

[0055] The change in the length of the partition 22 can affect the length of the combustion zone 23 and the cooling zone 24, and further affect the performance of the pulverized coal burner 10. By controlling the expansion and contraction of the partition 22 along the flow direction of the pulverized coal, the pulverized coal burner 10 can provide different lengths of the combustion zone 23 and the cooling zone 24 for different pulverized coal or working conditions, and further provide different ignition performances, thereby achieving a combustion process that better meets the requirements of various media or working conditions.

[0056] Moreover, the change in the length of the partition 22 also affects whether the tail end of the partition 22 extends to the outlet of the cylinder 21. It can be understood that when the tail end of the partition 22 does not extend to the outlet of the cylinder 21, but is located upstream of the outlet of the cylinder 21, there is a gap between the tail end of the partition 22 and the outlet of the cylinder 21. At this time, the area between the tail end of the partition 22 and the outlet of the cylinder 21 is located downstream of the partition 22, and is connected to the outlets of the combustion zone 23 and the cooling zone 24, so that the pulverized coal flowing out of the combustion zone 23 and the cooling zone 24 can be mixed. Therefore, the corresponding area can be called a mixing zone 25. That is to say, when there is a gap between the tail end of the partition 22 and the outlet of the cylinder 21, a mixing zone 25 is also provided in the cylinder 21. The mixing zone 25 is located downstream of the partition 22 along the flow direction of the pulverized coal, and the pulverized coal flowing out of the combustion zone 23 and the cooling zone 24 can be mixed in the mixing zone 25. In this way, the pulverized coal flowing out of the combustion zone 23 and the cooling zone 24 can be premixed before being ejected from the outlet of the barrel 21. This allows, on the one hand, the airflow of the cooling zone 24 to cool the pulverized coal airflow flowing out of the combustion zone 23, reduce the overall temperature of the pulverized coal airflow, and prevent the nozzle from being burned due to the excessive temperature of the pulverized coal airflow. On the other hand, the pulverized coal flowing out of the cooling zone 24 can be ignited by the flame transmitted from the combustion zone 23 before being ejected, making the flame intensity higher, the torch larger, and the flame propagation more stable. It can be seen that further setting the mixing zone 25 on the basis of the combustion zone 23 and the cooling zone 24 is conducive to further improving the performance of the pulverized coal burner 10. In case of providing the combustion zone 23, the cooling zone 24 and the mixing zone 25, not only can a biased combustion process with easy ignition, stable propagation and not prone to coking be achieved based on the cooperation of the combustion zone 23 and the cooling zone 24, but also after the biased combustion, the mixing zone 25 can be used to mix the two parts of coal powder flowing out of the combustion zone 23 and the cooling zone 24, so as to cool the coal powder and further intensify the combustion, thereby achieving a more sufficient and safer combustion process, and effectively improving the ignition performance and combustion safety of the coal powder burner 10, thereby achieving effective improvement in the performance of the coal powder burner 10.

[0057] It is not difficult to understand that the change in the length of the partition 22 also affects the change in the length of the mixing zone 25. By controlling the expansion and contraction of the partition 22, it is possible to control whether the pulverized coal burner 10 is provided with the mixing zone 25 and the length of the mixing zone 25, and then the pulverized coal burner 10 can provide different ignition performances for different pulverized coal or working conditions, and realize a combustion process that is more in line with the requirements of each medium or working condition. Among them, the shorter the length of the partition 22, the larger the interval between the tail end of the partition 22 and the outlet of the cylinder 21, the larger the mixing zone 25, and the earlier the pulverized coal flowing out of the combustion zone 23 and the cooling zone 24 is mixed. On the contrary, the longer the length of the partition 22, the smaller the interval between the tail end of the partition 22 and the outlet of the cylinder 21, the smaller the mixing zone 25, and the later the pulverized coal flowing out of the combustion zone 23 and the cooling zone 24 is mixed.

[0058] It can be seen that the downwardly biased and retractable partition 22 provided in the cylinder 21 can effectively improve the flexibility of the pulverized coal burner 10, so that the pulverized coal burner 10 can be effectively ignited for different media or different working conditions, and a stable and safe combustion process can be achieved.

[0059] exist Figure 1-3 In the figure, the dotted line on the right is only used to schematically indicate the extension and contraction of the partition 22. It is not used to specifically limit the extension and contraction range of the partition 22. In some embodiments, the partition 22 can be extended and contracted so that the length of the partition 22 accounts for 10%-100% of the total length of the cylinder 21. For example, the length of the partition 22 can account for 10%-80% of the total length of the cylinder 21.

[0060] In order to improve the flexibility of the use of the pulverized coal burner 10, in addition to configuring the partition plate 22 to be adjustable in length, other means may also be used. Figure 2-3 In some embodiments, the partition 22 includes a first plate segment 221 and a second plate segment 222, which are arranged in sequence along the flow direction of the pulverized coal, and the first plate segment 221 is connected to the second plate segment 222 so as to be rotatable up and down. In this way, by rotating the first plate segment 221 and changing the angle between the first plate segment 221 and the second plate segment 222, the flow area ratio of the combustion zone 23 and the cooling zone 24 can be changed, and the air volume and the amount of pulverized coal entering the combustion zone 23 and the cooling zone 24 can be flexibly allocated, so that the pulverized coal burner 10 can achieve a combustion effect that is more in line with the actual situation.

[0061] See also Figure 1-3In some embodiments, the ignition device 3 includes not only an ignition source 31, but also a first sleeve 32 and a second sleeve 33. The first sleeve 32 and the second sleeve 33 are arranged in the combustion zone 23. The first sleeve 32 is sleeved outside the ignition source 31. In other words, the ignition source 31 is inserted into the first sleeve 32. The second sleeve 33 is sleeved outside the first sleeve 32 and is staggered with the first sleeve 32 along the flow direction of the coal powder. Here, "staggered along the flow direction of the coal powder" means that the second sleeve 33 partially overlaps with the first sleeve 32 in the flow direction of the coal powder. At this time, the inlet of the second sleeve 33 is located between the inlet and the outlet of the first sleeve 32 along the flow direction of the coal powder, and the outlet of the second sleeve 33 is located downstream of the outlet of the first sleeve 32 along the flow direction of the coal powder.

[0062] The gap between the first sleeve 32 and the ignition source 31 can limit the amount of concentrated powder ignited in the initial stage of combustion, so that only a small amount of the concentrated powder entering the combustion zone 23 can enter the first sleeve 32 and be ignited by the ignition source 31. This can form a coal powder airflow with a small amount, high coal powder concentration and low flow rate at the ignition source 31, so that the energy of the ignition source 31 can effectively ignite this small amount of coal powder, because, under the same ignition source energy, the smaller the amount of coal powder, the higher the coal powder concentration, and the lower the coal powder flow rate, the easier it is for the coal powder to be ignited. At the same time, the first sleeve 32 is a local strengthening device, which can limit the unburned coal powder from entering the first sleeve 32, so as to prevent the unburned coal powder airflow from cooling and interfering with the initial flame, causing the initial flame to be extinguished. In other words, the first sleeve 32 can form a protection for the initial flame, play a local strengthening role, and make the initial flame easier to cultivate. It can be seen that the first sleeve 32 arranged outside the ignition source 31 in the combustion zone 23 is conducive to the cultivation of the initial flame and can improve the ignition performance by protecting the initial flame in the combustion zone 23.

[0063] Furthermore, a second sleeve 33 is further sleeved outside the first sleeve 32, so that the initial flame formed by the coal powder ignited by the ignition source 31 in the first sleeve 32 can enter the second sleeve 33, ignite more concentrated powder, form a larger flame, and achieve flame amplification, so that the flame can stably propagate downstream, improving the stability of flame propagation. It can be seen that the second sleeve 33 is an amplification device that can achieve a stable combustion process.

[0064] It can be seen that, on the basis of the partition plate 22, further setting the first sleeve 32 and / or the second sleeve 33 can effectively improve the combustion performance of the pulverized coal burner 10, which is particularly conducive to improving the ignition ability of the pulverized coal burner 10 for inferior coal, and solving the problems of insufficient ignition performance and easy burning of the pulverized coal burner using inferior coal in the related art. Inferior coal generally refers to coal with poor media such as inferior coal and high-moisture lignite. Due to high moisture, low calorific value or large particle size, there are problems such as difficulty in ignition, easy extinguishing of the initial flame, difficulty in cultivation, and difficulty in flame propagation. The pulverized coal burner in the related art is difficult to ignite effectively. By setting the offset partition plate 22 and the first sleeve 32 and / or the second sleeve 33 in the cylinder 21, the pulverized coal burner 10 can have excellent ignition and stable combustion performance, thereby breaking through the technical barrier of high difficulty in igniting inferior coal, so that even for inferior coal, effective ignition can be achieved.

[0065] In the related art, the aforementioned downward eccentrically arranged partition plate 22, the first sleeve 32 for local strengthening, and the second sleeve 33 for amplification are not simultaneously arranged in the pulverized coal burner 10.

[0066] The embodiment of the present application integrates the downward eccentric partition 22, the first sleeve 32 that plays a local strengthening role, and the second sleeve 33 that plays an amplifying role into the pulverized coal burner 10, so that the three can be coupled with the concentration device 1 and the ignition source 31, and the three can be coupled with each other, so as to give full play to the advantages of the three, realize an offset combustion process that is easy to ignite, and has stable and safe flame propagation, make the combustion process more intense, more stable, and safer, and effectively improve the ignition performance of the pulverized coal burner 10.

[0067] During operation, the primary air powder passes through the concentration device 1 and is divided into two streams, a concentrated powder and a light powder. After the concentrated powder and the light powder flow out of the concentration device 1, they flow to the combustion zone 23 and the cooling zone 24 respectively. Since the flow area of ​​the combustion zone 23 is larger than the flow area of ​​the cooling zone 24, after the concentrated powder and the light powder enter the combustion zone 23 and the cooling zone 24 respectively, a high-concentration and low-flow-rate coal powder airflow and a low-concentration and high-flow-rate coal powder airflow are formed in the combustion zone 23 and the cooling zone 24 respectively. Among them, a small part of the high-concentration and low-flow-rate coal powder airflow in the combustion zone 23 enters the space between the first sleeve 32 and the ignition source 31. In the gap, a coal powder airflow with a small amount, high concentration and low wind speed is formed at the ignition position, which is effectively ignited by the ignition source 31, cultivating a strong and stable initial flame, and continues to flow backward into the second sleeve 33, igniting more concentrated powder, making the flame stronger and propagating more stably, so that the concentrated powder entering the combustion zone 23 can be effectively ignited step by step under the action of the first sleeve 22 and the second sleeve 33, making the ignition ability stronger; while the low-concentration and high-flow rate coal powder airflow in the cooling zone 24 does not burn, but cools the combustion zone 23 to prevent coking in the combustion zone 23, making the combustion process safer.

[0068] The number of the second sleeve 33, which plays the role of amplifying the flame and stabilizing the combustion, is not limited to one. Figure 1 In some embodiments, the ignition device 3 includes at least two second sleeves 33, which are sequentially sleeved from the inside to the outside, and the at least two second sleeves 33 are staggered along the flow direction of the coal powder. Here, "staggered along the flow direction of the coal powder" means that two adjacent second sleeves 33 partially overlap in the flow direction of the coal powder. At this time, in the two adjacent second sleeves 33, the inlet of the rear second sleeve 33 is located between the inlet and outlet of the front second sleeve 33 along the flow direction of the coal powder, and the outlet of the rear second sleeve 33 is located downstream of the outlet of the front second sleeve 33 along the flow direction of the coal powder.

[0069] Since each second sleeve 33 can form a one-stage amplification device, when at least two second sleeves 33 are provided, the pulverized coal burner 10 has at least two-stage amplification devices, which can amplify the flame step by step, stabilize the combustion, and more effectively improve the ignition capability.

[0070] Also, see Figure 2 In some embodiments, the flow area of ​​the second sleeve 33 gradually increases along the flow direction of the pulverized coal. By setting the flow area of ​​the second sleeve 33 to gradually increase along the flow direction of the pulverized coal, the flow velocity of the pulverized coal can be gradually reduced when flowing through the second sleeve 33, which is conducive to more complete combustion of the pulverized coal, thereby further improving the ignition capability of the pulverized coal burner 10.

[0071] Below Figure 1-3 The illustrated embodiment is further described.

[0072] First, let’s introduce Figure 1 The first embodiment is shown.

[0073] like Figure 1 As shown, in this first embodiment, the pulverized coal burner 10 includes a concentration device 1, a combustion device 2 and an ignition device 3.

[0074] The concentrator 1 is an elbow-type concentrator, which includes an elbow 11. The elbow 11 uses centrifugal action to separate the coal powder into dense and thin phases. Inside the elbow 11, the radially outer portion is used as a dense phase area 14, and the radially inner portion is used as a dilute phase area 15, for the dense powder and the thin powder to flow respectively. The cross section of the elbow 11 can be various shapes such as round or square.

[0075] The combustion device 2 includes a cylinder 21 and a partition 22. The inlet of the cylinder 21 is directly connected to the outlet of the elbow 11. The cross section of the cylinder 21 can be various shapes such as round or square. The partition 22 is a plate-like structure extending along the flow direction of the coal powder, which is arranged in the cylinder 21 and is offset downward relative to the center of the cylinder 21. The head end of the partition 22 is flush with the inlet of the cylinder 21, that is, the partition 22 extends backward from the inlet of the cylinder 21. A gap is provided between the tail end of the partition 22 and the outlet of the cylinder 21. In this way, the space between the partition 22 and the part of the side wall of the cylinder 21 located above the partition 22 forms a combustion zone 23, the space between the partition 22 and the part of the side wall of the cylinder 21 located below the partition 22 forms a cooling zone 24, and the space between the tail end of the partition 22 and the outlet of the cylinder 21 forms a mixing zone 25. In this way, the combustion zone 23 and the cooling zone 24 are directly opposite each other and are respectively located above and below the partition 22, and the flow area of ​​the combustion zone 23 is larger than the flow area of ​​the cooling zone 24; and the mixing zone 25 is located downstream of the partition 22, and connects the outlet of the combustion zone 23 and the outlet of the cooling zone 24.

[0076] The ignition device 3 includes an ignition source 31, a first sleeve 32 and two second sleeves 33. The ignition source 31 is inserted into the combustion zone 23. When inserted, the angle between the ignition source 31 and the longitudinal center line of the cylinder 21 can be 0-90°, that is, the ignition source 31 can be inserted into the combustion zone 23 horizontally, vertically or obliquely, which can be adjusted according to factors such as the on-site installation space and the ignition effect and ignition safety. The first sleeve 32 and the two second sleeves 33 are both arranged in the cylinder 21. Among them, the first sleeve 32 is sleeved on the outside of the ignition source 31, and the gap between the first sleeve 32 and the ignition source 31 is 1-15mm, which plays a local strengthening role to facilitate the cultivation of the initial flame. The two second sleeves 33 are respectively called the first magnifying tube and the second magnifying tube, wherein the first magnifying tube is sleeved on the outside of the first sleeve 32 and partially overlaps with the first sleeve 32 in the direction of coal powder flow; the second magnifying tube is sleeved on the outside of the first magnifying tube and partially overlaps with the second magnifying tube in the direction of coal powder flow. The first magnifying tube and the second magnifying tube together magnify the flame step by step.

[0077] Depend on Figure 1 It can be seen that in the first embodiment, the first sleeve 32 and each second sleeve 33 are in a straight tube shape. However, it should be noted that the shapes of the first sleeve 32 and the second sleeve 33 are not limited to this, which will be described in detail later. Figure 2 This is also reflected in the embodiment shown.

[0078] The pulverized coal burner 10 of this embodiment can separate the concentrated powder into light powder and concentrate powder by using the bent pipe 11 to separate the primary air powder into concentrated powder and concentrate powder so that the concentrated powder and the light powder can directly enter the combustion zone 23 with a larger flow area and the cooling zone 24 with a smaller flow area, respectively, so as to form a low-speed but high-concentration atmosphere and a high-speed but low-concentration atmosphere in the combustion zone 23 and the cooling zone 24, respectively. The ignition source 31 first effectively ignites a small portion of the concentrated powder entering the combustion zone 23 under the protection of the first sleeve 32, and then cooperates with the step-by-step amplification effect of the two second sleeves 33 to realize the step-by-step combustion of the concentrated powder in the combustion zone 23. During the combustion process, the light powder in the cooling zone 24 can play a certain cooling role to prevent coking. Afterwards, the two pulverized coal airflows flowing out of the combustion zone 23 and the cooling zone 24 are mixed in the mixing zone 25 to further reduce the temperature and intensify the combustion, and finally are ejected from the outlet of the cylinder 21. During the whole process, ignition is easy, combustion is stable, and it is not easy to burn and coke, so that the pulverized coal burner 10 has good ignition performance for low-quality coal and high-moisture coal, and can effectively ignite low-quality coal and high-moisture coal.

[0079] Next, let’s introduce Figure 2-3 When introducing other embodiments, in order to simplify the description, only the differences from the embodiments are emphasized, and the similarities are not described in detail.

[0080] First, let’s introduce Figure 2The second embodiment is shown.

[0081] like Figure 2 As shown, the second embodiment differs from the first embodiment mainly in that the number and shape of the second sleeves 33 are different, and the partition plate 22 is constructed so that the inlet angle is adjustable.

[0082] Among them, Figure 2 As shown, in the second embodiment, the ignition device 3 includes only one second sleeve 33, and the flow area of ​​the second sleeve 33 is no longer constant, but gradually increases along the flow direction of the coal powder. Figure 2 It can be seen that in the second embodiment, the second sleeve 33 is in the shape of a cone that gradually expands along the flow direction of the coal powder.

[0083] Since the flow area of ​​the second sleeve 33 gradually increases along the flow direction of the pulverized coal, the second sleeve 33 can more effectively decelerate the pulverized coal to achieve more complete and stable combustion of the pulverized coal in the combustion zone 23 .

[0084] It can be understood that in order to further improve the combustion performance by reducing the speed of the coal powder, in the fourth embodiment, the first sleeve 32 can also be configured so that the flow area gradually increases along the flow direction of the coal powder.

[0085] In addition, if Figure 2 As shown, in this embodiment, the partition 22 includes a first plate segment 221 and a second plate segment 222. The first plate segment 221 and the second plate segment 222 are connected in sequence along the flow direction of the pulverized coal. Among them, the head end of the first plate segment 221 constitutes the head end of the partition 22, which is flush with the inlet of the cylinder 21. The tail end of the second plate segment 222 constitutes the tail end of the partition 22, which is arranged at intervals from the outlet of the cylinder 21. The tail end of the first plate segment 221 is connected to the head end of the second plate segment 222 in a rotatable manner up and down, so as to realize the rotatable connection between the first plate segment 221 and the second plate segment 222, so that the first plate segment 221 can change the inlet angle of the partition 22 by rotating up and down relative to the second plate segment 222, thereby changing the ratio of the flow area of ​​the combustion zone 23 and the cooling zone 24, so as to change the pulverized coal ratio of the combustion zone 23 and the cooling zone 24, and more flexibly adapt to different media and ignition conditions. Furthermore, the second plate section 222 is retractable, so that the length of the partition plate 22 is adjustable to change the lengths of the combustion zone 23, the cooling zone 24 and the mixing zone 25, so as to more flexibly adapt to different media and ignition conditions.

[0086] Among them, Figure 2As indicated by the two dotted lines on the left side of the figure, in this embodiment, the first plate segment 221 rotates relative to the second plate segment 222 within a range of ±30°. When the first plate segment 221 rotates to an angle of 0° between the first plate segment 221 and the second plate segment 222, the first plate segment 221 and the second plate segment 222 are in the same line, and both are parallel to the longitudinal center line of the cylinder 21. At this time, the inlet angle of the partition 22 is 0°. When the first plate segment 221 rotates to an angle of +30° between the first plate segment 221 and the second plate segment 222, the first plate segment 221 tilts upward relative to the second plate segment 222 (see Figure 2 At this time, the angle between the first plate segment 221 and the longitudinal centerline of the cylinder 21 is +30°, and the inlet angle of the partition 22 is greater than 0°, which is 30°. When the first plate segment 221 rotates to an angle of -30° with the second plate segment 222, the first plate segment 221 tilts downward relative to the second plate segment 222 (see Figure 2 At this time, the angle between the first plate segment 221 and the longitudinal center line of the cylinder 21 is -30°, and the inlet angle of the partition 22 is less than 0°, which is -30°.

[0087] Next, let’s introduce Figure 3 The third embodiment is shown.

[0088] like Figure 3 As shown, the difference between the third embodiment and the first and second embodiments is that the mixing zone 25 is no longer of uniform cross-section, but includes a tapered section 251. Along the flow direction of the pulverized coal, the flow area of ​​the tapered section 251 gradually decreases. Specifically, the tapered section 251 is in a tapered shape that gradually decreases along the flow direction of the pulverized coal. Figure 3 It can be seen that, in this embodiment, the mixing zone 25 further includes a section of equal cross section, and the section of equal cross section is connected to the end of the tapered section 251 .

[0089] The tapered section 251 can guide the two parts of coal powder flowing out of the combustion zone 23 and the cooling zone 24 to mix more fully and quickly, play a rectifying role, reduce turbulence, and at the same time, it is also conducive to accelerating the coal powder spraying flow rate.

[0090] In the above embodiments, the partition plate 22 may be a flat plate or a curved plate. Figure 4 In some embodiments, the partition 22 is an arc-shaped plate, a cross section of which is an arc surface, and the partition 22 is concave downward.

[0091] Compared with the case where the partition 22 is a flat plate, when the partition 22 is an arc-shaped plate, the transition at the connection between the two ends of the partition 22 and the side wall of the cylinder 21 is smoother and the resistance is smaller, which can make the flow field smoother, avoid the low-speed area and powder accumulation at the side wall, and improve ignition safety.

[0092] In addition, when the partition 22 is offset and the cross-section of the cylinder 21 is circular, if the partition 22 is a flat plate, the top wall of the combustion zone 23 is the side wall of the cylinder 21, which is arc-shaped, and the bottom wall of the combustion zone 23 is the partition 22, which is a straight plate. At this time, the combustion zone 23 is asymmetrical up and down, and the offset ignition source 31 located in the center of the combustion zone 23 deviates further from the overall center of the pulverized coal burner 10, which is not conducive to the uniformity of combustion and easily causes the flame to brush the wall, causing coking problems; and when the partition 22 is an arc-shaped plate, such as Figure 4 As shown, the top wall and the bottom wall of the combustion zone 23 are both arc-shaped, which is conducive to a smooth and nearly symmetrical distribution in the combustion zone 23. In this case, the advantage of the ignition center offset can be retained, and the offset ignition center can be relatively close to the overall center of the pulverized coal burner 10, thereby reducing the risk of coking.

[0093] Meanwhile, continue to see Figure 4 In some embodiments, the outlet of the cylinder 21 is circular, so that it is convenient to cooperate with the boiler wind box, so that the pulverized coal burner 10 can be flexibly installed according to the on-site conditions and has good on-site adaptability.

[0094] In summary, the pulverized coal burner 10 provided in the embodiment of the present invention has a simple structure, is flexible to use, and has superior performance, and is conducive to solving the ignition and stable combustion problems of inferior coal types such as low-quality coal and high-moisture coal.

[0095] The pulverized coal burner 10 provided in the embodiment of the present invention is applied to a combustion system, which can effectively improve the performance of the combustion system. Therefore, the embodiment of the present invention also provides a combustion system, which includes a boiler and the pulverized coal burner 10 of each embodiment of the present invention.

[0096] The above description is only an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pulverized coal burner (10), characterized in that: include: A concentrator (1) is an elbow-type concentrator, a straight tube block-type concentrator or a shutter-type concentrator, which separates the coal powder into concentrated powder and light powder; A combustion device (2), comprising a cylinder (21) and a partition (22), wherein the inlet of the cylinder (21) is connected to the outlet of the concentration device (1), the partition (22) is eccentrically arranged downward in the cylinder (21), and divides the internal space of the cylinder (21) into a combustion zone (23) and a cooling zone (24), the combustion zone (23) is located above the partition (22) and is used to receive the concentrated coal powder, and the cooling zone (24) is located below the partition (22) and is used to receive the light coal powder, and the partition (22) is retractable and comprises a first plate segment (221) and a second plate segment (222), the first plate segment (221) and the second plate segment (222) are arranged in sequence along the flow direction of the coal powder, and the first plate segment (221) is connected to the second plate segment (222) in a rotatable manner up and down to change the flow area ratio between the combustion zone (23) and the cooling zone (24); and An ignition device (3) comprises an ignition source (31), wherein the ignition source (31) is inserted into the combustion zone (23).

2. The pulverized coal burner (10) according to claim 1, characterized in that: The partition (22) is extended and retracted so that the length of the partition (22) accounts for 10%-100% of the total length of the cylinder (21).

3. The pulverized coal burner (10) according to claim 1, characterized in that: The first plate segment (221) is located relative to the second plate segment (222). Rotate within the range.

4. The pulverized coal burner (10) according to claim 1, characterized in that: A mixing zone (25) is also provided in the cylinder (21). The mixing zone (25) is located downstream of the partition (22) along the flow direction of the pulverized coal. The pulverized coal flowing out of the combustion zone (23) and the cooling zone (24) is mixed in the mixing zone (25).

5. The pulverized coal burner (10) according to claim 4, characterized in that: The mixing zone (25) comprises a tapered section (251), and along the flow direction of the pulverized coal, the flow area of ​​the tapered section (251) gradually decreases.

6. The pulverized coal burner (10) according to any one of claims 1 to 5, characterized in that: The cross section of the partition (22) is a curved surface.

7. The pulverized coal burner (10) according to any one of claims 1 to 5, characterized in that: The ignition device (3) further comprises a first sleeve (32), wherein the first sleeve (32) is arranged in the combustion zone (23) and sleeved on the outside of the ignition source (31).

8. The pulverized coal burner (10) according to claim 7, characterized in that: Along the flow direction of the coal powder, the flow area of ​​the first sleeve (32) gradually increases.

9. The pulverized coal burner (10) according to claim 7, characterized in that: The ignition device (3) further comprises a second sleeve (33) arranged in the combustion zone (23); the second sleeve (33) is sleeved outside the first sleeve (32) and is arranged offset with the first sleeve (32) along the flow direction of the coal powder.

10. The pulverized coal burner (10) according to claim 9, characterized in that: Along the flow direction of the coal powder, the flow area of ​​the second sleeve (33) gradually increases.

11. A combustion system, comprising a boiler, characterized in that: It also comprises a pulverized coal burner (10) as claimed in any one of claims 1 to 10, wherein the outlet of the cylinder (21) is connected to the interior of the boiler.

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