CN112781035A - Offset pulverized coal burner and combustion system - Google Patents
Offset pulverized coal burner and combustion system Download PDFInfo
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- CN112781035A CN112781035A CN202110290845.9A CN202110290845A CN112781035A CN 112781035 A CN112781035 A CN 112781035A CN 202110290845 A CN202110290845 A CN 202110290845A CN 112781035 A CN112781035 A CN 112781035A
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- 239000003245 coal Substances 0.000 title claims abstract description 238
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 167
- 238000005192 partition Methods 0.000 claims abstract description 91
- 239000000843 powder Substances 0.000 claims abstract description 88
- 238000001816 cooling Methods 0.000 claims abstract description 60
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- 239000002245 particle Substances 0.000 description 2
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D1/00—Burners for combustion of pulverulent fuel
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D2201/00—Burners adapted for particulate solid or pulverulent fuels
- F23D2201/20—Fuel flow guiding devices
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- Engineering & Computer Science (AREA)
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- Combustion & Propulsion (AREA)
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Abstract
The invention relates to the technical field of pulverized coal combustion, in particular to an offset pulverized coal burner and a combustion system. Wherein, the bias pulverized coal burner includes: the concentration device is used for separating the coal powder into thick powder and light powder; the combustion device comprises a cylinder and a partition plate, wherein an inlet of the cylinder is communicated with an outlet of the concentration device, the partition plate is eccentrically arranged in the cylinder downwards and divides the inner space of the cylinder into a combustion area and a cooling area, the combustion area is positioned above the partition plate and used for receiving thick powder, the cooling area is positioned below the partition plate and used for receiving light powder, a mixing area is also arranged in the cylinder, and the mixing area is positioned at the downstream of the partition plate along the flowing direction of pulverized coal and is communicated with the outlet of the combustion area and the outlet of the cooling area; and an ignition device including an ignition source inserted into the combustion region. Thus, the ignition performance of the pulverized coal burner can be effectively improved.
Description
Technical Field
The invention relates to the technical field of pulverized coal combustion, in particular to an offset pulverized coal burner and a combustion system.
Background
Pulverized coal burners have been widely used in coal-fired utility boilers. However, ignition performance of the pulverized coal burner in the related art still needs to be improved, and particularly, the pulverized coal burner is difficult to effectively ignite poor-quality coal with high moisture, low calorific value or large pulverized coal particle size.
Disclosure of Invention
The embodiment of the invention aims to solve the technical problem that: the ignition performance of the pulverized coal burner is improved.
In order to solve the above technical problem, an embodiment of the present invention provides an offset pulverized coal burner, including:
the concentration device is used for separating the coal powder into thick powder and light powder;
the combustion device comprises a cylinder and a partition plate, wherein an inlet of the cylinder is communicated with an outlet of the concentration device, the partition plate is eccentrically arranged in the cylinder downwards and divides the inner space of the cylinder into a combustion area and a cooling area, the combustion area is positioned above the partition plate and used for receiving thick powder, the cooling area is positioned below the partition plate and used for receiving light powder, a mixing area is also arranged in the cylinder, and the mixing area is positioned at the downstream of the partition plate along the flowing direction of pulverized coal and is communicated with the outlet of the combustion area and the outlet of the cooling area; and
an ignition device includes an ignition source inserted into the combustion region.
In some embodiments, the mixing zone comprises a tapered section having a gradually decreasing flow area along the direction of flow of the coal fines.
In some embodiments, the partition comprises a first plate section and a second plate section, the first plate section and the second plate section are sequentially arranged along the flow direction of the pulverized coal, and the first plate section is rotatably connected with the second plate section up and down to change the flow area ratio of the combustion zone and the cooling zone.
In some embodiments, the first plate segment rotates within ± 30 ° relative to the second plate segment.
In some embodiments, the baffle is adjustable in length.
In some embodiments, the length of the mixing zone is 20% to 90% of the total barrel length.
In some embodiments, the ignition source is located in the center of the combustion zone.
In some embodiments, the cross-section of the baffle is a curved surface.
In some embodiments, the ignition device further comprises a first sleeve disposed within the combustion region and sleeved outside the ignition source.
In some embodiments, the gap between the first sleeve and the ignition source is 1-15 mm.
In some embodiments, the ignition device further comprises a second sleeve disposed in the combustion zone, the second sleeve being disposed outside the first sleeve and being offset from the first sleeve in the flow direction of the pulverized coal.
In some embodiments, the ignition device includes at least two second sleeves, the at least two second sleeves are sequentially sleeved from inside to outside, and the at least two second sleeves are arranged along the flow direction of the pulverized coal in a staggered manner.
In some embodiments, the flow area of the second sleeve gradually increases along the flow direction of the pulverized coal.
In some embodiments, the inlet of the cartridge is in direct communication with the outlet of the concentration device.
In some embodiments, the barrel comprises a first barrel section and a second barrel section, the first barrel section connects the concentrating device and the second barrel section, and the flow area of the first barrel section gradually increases along the flow direction of the pulverized coal.
In some embodiments, the flow area of the combustion zone is greater than the flow area of the concentrator inlet.
In some embodiments, the concentration device comprises an elbow, the inlet and outlet of the elbow forming the inlet and outlet, respectively, of the concentration device, and the concentration device further comprises:
the bent plate is arranged in the bent pipe and extends along the longitudinal center line of the bent pipe; and/or the presence of a gas in the gas,
and the stop block is arranged on the inner surface of the side wall of the elbow pipe positioned at the radial outer side.
In some embodiments, the bend plate is eccentrically disposed in the bend tube toward the radially outer side.
In some embodiments, the flexural plate is rectangular, arcuate, V-shaped, or double V-shaped in cross-section, or the flexural plate is a torsional plate.
The embodiment of the invention also provides a combustion system which comprises a boiler and the offset pulverized coal burner of the embodiment of the invention, wherein the outlet of the cylinder is communicated with the interior of the boiler.
The ignition performance of the pulverized coal burner can be effectively improved by arranging the downward eccentric partition plate to divide the interior of the cylinder into a combustion area, a cooling area and a mixing area.
Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic cross-sectional view of an offset pulverized coal burner in a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of an offset pulverized coal burner in a second embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view of an offset pulverized coal burner in a third embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view of an offset pulverized coal burner in a fourth embodiment of the present invention.
FIG. 5 is a schematic cross-sectional view of an offset pulverized coal burner in a fifth embodiment of the present invention.
FIG. 6 is a schematic cross-sectional view of an offset pulverized coal burner in a sixth embodiment of the present invention.
FIG. 7 is a schematic sectional view of an offset pulverized coal burner in a seventh embodiment of the present invention.
FIG. 8 is a schematic sectional view of an offset pulverized coal burner in an eighth embodiment of the present invention.
Figure 9 illustrates the shape of the spacer in some embodiments of the invention.
FIG. 10 illustrates the shape of a flexural plate in some embodiments of this invention.
Fig. 11 shows a first variation of the shape of the bent plate.
Fig. 12 shows a second variation of the bent plate shape.
Fig. 13 shows a third variation of the bent plate shape.
Fig. 14 shows a fourth variation of the bent plate shape.
Description of reference numerals:
10. biasing the pulverized coal burner;
1. a concentration device; 11. bending the pipe; 12. bending a plate; 121. a first plate portion; 122. a second plate portion; 123. a third plate portion; 124. a fourth plate portion; 13. a stopper; 14. a dense phase zone; 15. a dilute phase zone; 16. a straight pipe;
2. a combustion device; 21. a barrel; 211. a first barrel section; 212. a second barrel section; 22. a partition plate; 221. a first plate section; 222. a second plate section; 23. a combustion zone; 24. a cooling zone; 25. a mixing zone; 251. a tapered section;
3. an ignition device; 31. an ignition source; 32. a first sleeve; 33. a second sleeve.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without any inventive step, are within the scope of the present invention.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In the description of the present invention, it should be understood that, for convenience of describing the present invention and simplifying the description, the orientation or positional relationship indicated by the orientation words such as "upper, lower, left, right, front, rear", "lateral, vertical, horizontal" and "top, bottom" etc. is generally based on the orientation or positional relationship when the offset pulverized coal burner is normally placed and installed as shown in the drawings; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.
In the description of the present invention, it should be understood that the terms "first", "second", etc. are used to define the components, and are used only for the convenience of distinguishing the corresponding components, and if not otherwise stated, the terms have no special meaning, and thus, should not be construed as limiting the scope of the present invention.
In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Fig. 1-14 illustrate an exemplary offset pulverized coal burner configuration of the present invention.
Referring to fig. 1 to 8, the pulverized coal burner includes a concentration device 1, a combustion device 2, and an ignition device 3.
The concentrator 1 and the burner 2 are connected in series along the direction of flow of the coal dust. The ignition device 3 is inserted into the combustion device 2. The concentration device 1 is connected to a primary air duct (not shown in the figure) and the combustion device 2, and is configured to separate the pulverized coal airflow conveyed by the primary air duct into thick powder with a relatively high pulverized coal concentration and thin powder with a relatively low pulverized coal concentration, and guide the thick powder and the thin powder to flow to the combustion device 2. The combustion device 2 is connected with the concentration device 1 and the boiler and is used for receiving the thick powder and the thin powder separated by the concentration device 1 for ignition by the ignition device 3. The ignition device 3 ignites the pulverized coal flowing into the combustion device 2. After being ignited by the ignition device 3, the pulverized coal is discharged from the outlet of the combustion device 2 into the boiler.
The coal powder is subjected to concentration separation, so that the method is favorable for strengthening ignition, stabilizing combustion and reducing NOXDischarging, and preventing hearth slagging and high-temperature corrosion. The flow-through regions of the dense-phase powder and the dilute-phase powder in the concentration device 1 can be referred to as a dense-phase region 14 and a dilute-phase region 15, respectively. That is, the thickening apparatus 1 has a dense-phase zone 14 and a dilute-phase zone 15 for passing dense meal and dilute meal, respectively.
The concentration device 1 can adopt various structural forms to realize the concentration separation of the coal powder.
For example, referring to fig. 1-7, in some embodiments, the concentrator device 1 includes an elbow 11. When the coal dust separator works, the bent pipe 11 performs concentration separation on coal dust by using a centrifugal effect. During the process of flowing through the bent pipe 11, the pulverized coal is divided into thick powder positioned on the radial outer side and thin powder positioned on the radial inner side under the action of centrifugal force, so that the thick-thin separation of the pulverized coal on the radial direction of the bent pipe 11 is realized. It can be understood that, at this time, the inlet and the outlet of the elbow 11 form the inlet and the outlet of the concentration device 1, respectively, the tube cavity of the elbow 11 forms the concentration zone, and the part of the tube cavity of the elbow 11 located at the radial outer side and the part located at the radial inner side form the dense phase zone 14 and the dilute phase zone 15, respectively, so that the dense phase zone 14 is located at the radial outer side of the dilute phase zone 15, or the dense phase zone 14 is located above the dilute phase zone 15, and dense powder and light powder are distributed up and down. The thickener 1 in this case may be referred to as an elbow thickener.
For another example, referring to fig. 8, in some embodiments, the concentrator 1 no longer includes the curved pipe 11, but includes the straight pipe 16, and the stopper 13 is disposed in the straight pipe 16, and the stopper 13 is disposed on the inner surface of the bottom wall of the straight pipe 16. Thus, the stop block 13 can change the moving direction of the coal powder, guide the coal powder to gather upwards and realize the separation of the upper and lower concentration of the coal powder. In the working process, the coal dust flowing into the straight pipe 16 is gathered to the upper part after meeting the stop block 13, so that the coal dust concentration in the upper space of the straight pipe 16 is higher to form a concentrated phase region 14, and meanwhile, the coal dust concentration in the lower space of the straight pipe is lower to form a dilute phase region 15. The thickener 1 in this case may be referred to as a block thickener.
Instead of the elbow structure shown in fig. 1-7 and the stopper structure shown in fig. 8, the concentrator 1 may also be in the form of a shutter or other structures. When a louvered configuration is used, the concentrator 1 may be referred to as a louvered concentrator.
The combustion device 2 provides space for the combustion of pulverized coal. The combustion apparatus 2 includes a cylinder 21. The cylinder 21 is hollow inside. The inlet and outlet of the cylinder 21 form the inlet and outlet of the combustion device 2, respectively, and are communicated with the outlet of the concentration device 1 and the interior of the boiler, respectively.
The ignition device 3 ignites the pulverized coal to realize combustion of the pulverized coal. The ignition device 3 comprises an ignition source 31. An ignition source 31 is inserted into the cylinder 21 to ignite the pulverized coal. The ignition source 31 may be embodied as various types of ignition means such as a plasma torch or an oil gun.
In order to improve the ignition performance of the pulverized coal burner, the embodiment of the invention improves the structure of the pulverized coal burner.
Referring to fig. 1-8, in some embodiments, a baffle 22 is provided in the combustion apparatus 2. The partition 22 is provided in the cylinder 21 and extends in a length direction of the cylinder 21 (a direction from an inlet of the cylinder 21 to an outlet of the cylinder 21) to partition an inner space of the cylinder 21 such that the inside of the cylinder 21 is partitioned into different regions.
Specifically, as shown in fig. 1-8, in some embodiments, a baffle 22 is eccentrically disposed in the barrel 21 facing downward and divides the interior space of the barrel 21 into a combustion zone 23 and a cooling zone 24. The combustion zone 23 is located above the partition 22 and communicates with the dense phase zone 14 for receiving the dense powder. A cooling zone 24 is located below the partition 22 and communicates with the freeboard 15 for receiving the dilute fines. Ignition source 31 is specifically inserted into combustion region 23 when inserted into barrel 21. The ignition source 31 is not provided in the cooling zone 24.
Since the partition plate 22 is not centrally disposed in the cylinder 21 but eccentrically disposed with the eccentric direction being downward eccentric, that is, the partition plate 22 is disposed below the longitudinal center line (center line from the inlet to the outlet) of the cylinder 21, the eccentric direction being in accordance with the direction in which the thin powder separated by the concentrating device 1 is located with respect to the thick powder, that is, the partition plate 22 is offset with respect to the cylinder 21 toward the side on which the thin powder is located, or the partition plate 22 is offset with respect to the cylinder 21 toward the side close to the dilute phase region 15, the flow area of the combustion region 23 for receiving the thick powder and having the ignition source 31 inside is larger than the flow area of the cooling region 24 for receiving the thin powder and having no ignition source 31 inside, for example, in some embodiments, the flow area of the combustion region 23 accounts for more than 50% and less than or equal to 90% of the total flow area of the cylinder 21, and the flow area of the cooling region 24 accounts for less than 50% of the total flow area of the cylinder 21, and is greater than or equal to 10%. Thus, on the one hand, the partition plate 22 can perform an offset concentration process to perform more sufficient and effective concentration and dilution separation of pulverized coal together with the concentration device 1, and 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 to perform an offset combustion process.
In the above-mentioned bias concentration process, the dense powder and the weak powder separated by the concentration device 1 enter the combustion zone 23 and the cooling zone 24 respectively, and are separated by the partition plate 22, and under the further separation action of the partition plate 22, the dense powder and the weak powder flowing from the concentration device 1 to the cylinder 21 are not mixed again before and during the ignition by the ignition source 31, so that a more reliable and more sufficient dense-weak separation effect can be realized.
In addition, in the above-mentioned offset combustion process, the combustion area 23 with a large flow area can fully receive the thick powder, and is favorable for reducing the flow speed of the thick powder, so that the atmosphere with high coal powder concentration and low coal powder speed can be formed in the combustion area 23, which is favorable for the ignition source 31 inserted into the combustion area 23 to smoothly ignite the thick powder, and meanwhile, the cooling area 24 with a small flow area can fully receive the light powder, and is favorable for improving the light powder speed, so that the atmosphere with low coal powder concentration and high coal powder speed can be formed in the cooling area 24, which is favorable for fully cooling the combustion area 23 by the coal powder in the cooling area 24 without the ignition source 31, and has the effect of preventing coking in the combustion area 23.
It can be seen that the partition plate 22 eccentrically arranged downwards separates the interior of the cylinder 21 into the combustion zone 23 provided with the ignition source 31 and the cooling zone 24 not provided with the ignition source 31, so that the pulverized coal burner becomes an offset pulverized coal burner 10, the offset pulverized coal burner 10 can perform offset concentration and offset combustion, the concentrated powder is smoothly and fully ignited under the condition of difficult coking, and a better combustion effect is realized.
In addition, the combustion zone 23 and the cooling zone 24 separated by the partition plate 22 are distributed up and down, but not distributed inside and outside, and other distribution relations, so that the partition plate 22 is not a cylindrical structure but a plate-shaped structure, which enables the offset pulverized coal burner 10 to realize the separation of the combustion zone 23 and the cooling zone 24 without any inner and outer sleeve structure, and simultaneously, the cylinder 21 is directly connected with the concentration device 1, the concentrated powder can smoothly enter the combustion zone 23 to form the pulverized coal airflow with high concentration and low flow rate, and a transition structure for guiding the concentrated powder to flow to the combustion zone 23 is not needed to be arranged between the combustion zone 23 and the cooling zone, thereby being beneficial to simplifying the structure of the offset pulverized coal burner 10. In addition, the combustion zone 23 and the cooling zone 24 are obtained by only separating the offset clapboard 22, and the device also has the advantages of small internal resistance, strong ignition performance and strong anti-powder-deposition and anti-coking capability. Because, when the combustion zone 23 and the cooling zone 24 are distributed internally and externally, the internal resistance of the combustion device 2 is large, and the annular gap between the inner sleeve and the outer sleeve is prone to the phenomenon of uneven distribution of wind speed and pulverized coal, which causes the problem of powder accumulation or burning loss. Meanwhile, when a transition structure is arranged between the inlet of the cylinder 21 and the outlet of the concentration device 1, the internal resistance is increased, powder is easy to accumulate at the transition structure, and the accumulated powder is easy to burn after the temperature rises, so that the pulverized coal burner is burnt out. And, when setting up transition structure guide dense powder and flowing to combustion area 23, the buggy concentration of transition structure entrance is high, and the velocity of flow is fast, causes transition structure wearing and tearing easily, influences the life of pulverized coal burner. In the embodiment of the invention, a transition structure is cancelled, so that the inlet of the cylinder 21 is directly communicated with the outlet of the concentration device 1, and based on the offset partition plate 22, a high-concentration and low-flow-rate atmosphere is formed in the combustion zone 23, thereby being beneficial to reducing the abrasion of the pulverized coal burner and prolonging the service life of the offset pulverized coal burner 10.
Wherein the flow area of the combustion zone 23, which is divided by the partition 22, may be larger than the flow area of the inlet of the concentrating device 1. Since the flow area of the inlet of the concentrator 1 is generally equal to the flow area of the outlet of the primary air duct. Thus, when the flow area of the combustion zone 23 is greater than the flow area of the inlet of the concentrator 1, it means that the flow area of the combustion zone 23 is greater than the flow area of the outlet of the primary air duct. In this case, the combustion zone 23 may be said to be of an expanded design.
When the combustion zone 23 adopts an expansion design, the flow velocity of the pulverized coal airflow in the combustion zone 23 is favorably reduced, so that the pulverized coal is easier to ignite.
In some embodiments, the ratio of the flow area of the combustion zone 23 to the inlet flow area of the concentrator 1 is greater than 1 and less than or equal to 3. At this time, the expansion ratio of the combustion zone 23 may be said to be greater than 1 and less than or equal to 3.
Referring additionally to fig. 1-8, in some embodiments, a mixing zone 25 is also provided within the barrel 21. The mixing zone 25 is located downstream of the partition 22 in the direction of flow of the pulverized coal and communicates with both the outlet of the combustion zone 23 and the outlet of the cooling zone 24. As shown in fig. 1-8 in particular, in some embodiments, when extending from the inlet of the barrel 21 to the outlet of the barrel 21, the head end of the partition 22, i.e. the end of the partition 22 which is most upstream in the flow direction of the pulverized coal, is flush with the inlet of the cylinder 21, i.e. the partition 22 extends from the inlet of the cylinder 21 towards the outlet of the cylinder 21, while the trailing end of the partition plate 22, i.e. the end of the partition plate 22 that is most downstream in the direction of flow of the pulverized coal, does not extend to be flush with the outlet of the cylinder 21, but extends upstream of the outlet of the cylinder 21, spaced from the outlet of the barrel 21, in which case the region between the rear end of the partition 22 and the outlet of the barrel 21 forms a mixing zone 25, in this case, the mixing region 25 extends from the rear end of the partition 22 to the outlet of the cylinder 21, in other words, the outlet of the mixing region 25 is the outlet of the cylinder 21.
Based on the above arrangement, the pulverized coal flowing out from the combustion zone 23 and the cooling zone 24 can flow into the mixing zone 25 to be mixed, that is, the pulverized coal flowing out from the combustion zone 23 and the cooling zone 24 can be premixed before being sprayed out from the outlet of the barrel 21, so that, on one hand, the pulverized coal airflow flowing out from the combustion zone 23 can be cooled by the airflow of the cooling zone 24, the overall temperature of the pulverized coal airflow is reduced, nozzle burnout caused by overhigh temperature of the pulverized coal airflow is prevented, on the other hand, the pulverized coal flowing out from the cooling zone 24 can be ignited by the flame transmitted out from the combustion zone 23 before being sprayed out, the flame intensity is higher, the torch is larger, and the flame propagation is more stable.
It can be seen that the downward offset partition plate 22 is arranged to simultaneously separate the combustion zone 23, the cooling zone 24 and the mixing zone 25 from the interior of the cylinder 21, so that not only can an offset combustion process with easy ignition, stable propagation and difficult coking be realized based on the cooperation of the combustion zone 23 and the cooling zone 24, but also after offset combustion, the mixing zone 25 can be used for mixing two parts of pulverized coal flowing out from the combustion zone 23 and the cooling zone 24, the pulverized coal is cooled and further combusted in an enhanced manner, a more sufficient and safer combustion process is realized, the ignition performance and the combustion safety of the offset pulverized coal burner 10 are effectively improved, the performance of the offset pulverized coal burner 10 is effectively improved, and the problems of insufficient ignition performance, easy burning loss and the like of the pulverized coal burner combusting low-quality coal in the related technology can be solved. Poor quality coal, such as poor quality coal and high moisture lignite, which have poor media, have problems in that ignition is difficult, initial flame is easily extinguished, difficult to grow, and flame propagation is difficult, and the related art pulverized coal burner is difficult to effectively ignite. In the embodiment of the invention, the offset partition plate 22 is arranged in the pulverized coal burner, and the combustion zone 23, the cooling zone 24 and the mixing zone 25 are simultaneously separated from the inner part of the cylinder 21, so that the pulverized coal burner becomes the offset pulverized coal burner 10 with excellent ignition and stable combustion performance, the technical obstacle of high ignition difficulty of inferior coal can be broken through, and the effective ignition can be realized even aiming at the inferior coal.
Wherein the length of the mixing zone 25 may be 20% to 90% of the total length of the barrel 21. For example, in some embodiments, the partition 22 extends from the inlet of the cylinder 21 to the outlet of the cylinder 21, and the length of the partition 22 is 10% -80% of the total length of the cylinder 21, in which case the length of the mixing region 25 is 20% -90% of the total length of the cylinder 21. It is understood that the length refers to a dimension in a flow direction of the pulverized coal, or, in a direction from an inlet of the drum 21 to an outlet of the drum 21.
The variation in the ratio of the length of the mixing zone 25 to the length of the barrel 21 can be achieved by providing baffles 22 of different lengths in different offset pulverized coal burners 10 or by providing baffles 22 of adjustable lengths in the same offset pulverized coal burner 10. For example, in some embodiments, the partition 22 is retractable along the pulverized coal flow direction, at this time, for the same offset pulverized coal burner 10, the length of the partition 22 is not fixed, but can be flexibly changed by being retractable, which is beneficial to improving the use flexibility of the offset pulverized coal burner 10, so that the offset pulverized coal burner 10 can control the size of the mixing zone 25 for different media or different ignition conditions, and further provide different ignition performance for different pulverized coals or different operating conditions, thereby implementing a combustion process more conforming to the requirements of each medium or operating condition. It will be appreciated that the shorter the length of the partition 22, the greater the separation between the rear end of the partition 22 and the outlet of the barrel 21, the larger the mixing zone 25 and the earlier the coal dust flowing from the combustion zone 23 and the cooling zone 24 will mix, whereas the longer the length of the partition 22, the smaller the separation between the rear end of the partition 22 and the outlet of the barrel 21, the smaller the mixing zone 25 and the later the coal dust flowing from the combustion zone 23 and the cooling zone 24 will mix.
To increase the flexibility of use of the offset pulverized coal burner 10, other means may be employed in addition to the partition 22 being configured to be adjustable in length. For example, referring to fig. 1-8, in some embodiments, the partition 22 includes a first plate section 221 and a second plate section 222, the first plate section 221 and the second plate section 222 are sequentially arranged along the flow direction of the pulverized coal, and the first plate section 221 is rotatably connected to the second plate section 222 up and down. Thus, by rotating the first plate section 221 and changing the angle between the first plate section 221 and the second plate section 222, the flow area ratio of the combustion area 23 and the cooling area 24 can be changed, and the air volume and the pulverized coal volume entering the combustion area 23 and the cooling area 24 can be flexibly distributed, so that the offset pulverized coal burner 10 can achieve a combustion effect more conforming to actual conditions.
With continued reference to fig. 1-8, in some embodiments, the ignition device 3 includes not only the ignition source 31, but also a first sleeve 32 and a second sleeve 33. The first sleeve 32 and the second sleeve 33 are disposed within 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 arranged in a staggered manner with the first sleeve 32 along the flow direction of the pulverized coal. Here, "staggered in the pulverized coal flow direction" means that the second sleeve 33 partially overlaps the first sleeve 32 in the pulverized coal flow direction, in which case the inlet of the second sleeve 33 is located between the inlet and the outlet of the first sleeve 32 in the pulverized coal flow direction, and the outlet of the second sleeve 33 is located downstream of the outlet of the first sleeve 32 in the pulverized coal flow direction.
The gap between the first sleeve 32 and the ignition source 31 can limit the amount of the ignited thick powder at the initial stage of combustion, so that only a small strand of the thick powder entering the combustion region 23 can enter the first sleeve 32 and be ignited by the ignition source 31, and a small amount of coal powder airflow with high coal powder concentration and low flow rate can be formed at the ignition source 31, so that the small amount of coal powder can be effectively ignited by the energy of the ignition source 31. Meanwhile, the first sleeve 32 is a local strengthening device, which can limit unburned coal powder from entering the first sleeve 32, so as to prevent the initial flame from being extinguished due to the cooling and interference of the airflow of the unburned coal powder, that is, the first sleeve 32 can protect the initial flame, so as to play a role of local strengthening, and make the initial flame easier to be cultivated. It can be seen that the first sleeve 32 arranged in the combustion region 23 and sleeved outside the ignition source 31 is beneficial to the cultivation of initial flame, and the ignition performance can be improved by protecting the initial flame in the combustion region 23.
In addition, the second sleeve 33 is further sleeved outside the first sleeve 32, so that initial flame formed by the pulverized coal ignited by the ignition source 31 in the first sleeve 32 can enter the second sleeve 33, more concentrated powder is ignited, larger flame is formed, the amplification of the flame is realized, the flame is conveniently stabilized and propagated downstream, and the stability of flame propagation is improved. It can be seen that the provision of the second sleeve 33, which is an amplifying device, enables a stable combustion process to be achieved.
It can be seen that, on the basis of the partition plate 22, the first sleeve 32 and/or the second sleeve 33 are further arranged, so that the combustion performance of the offset pulverized coal burner 10 can be effectively improved, which is particularly beneficial to improving the ignition capability of the offset pulverized coal burner 10 on the low-quality coal, and solving the problems of insufficient ignition performance, easy burning loss and the like of the pulverized coal burner for combusting the low-quality coal in the related art. The low-grade coal generally refers to coal with poor media, such as low-grade coal and high-moisture lignite, and has problems of difficult ignition, easy extinction of initial flame, difficult cultivation, difficult flame propagation and the like due to high moisture, low calorific value, large particle size and the like, and the pulverized coal burner in the related art is difficult to ignite effectively. By arranging the offset partition plate 22 and the first sleeve 32 and/or the second sleeve 33 in the cylinder 21, the offset pulverized coal burner 10 has excellent ignition and stable combustion performance, so that the technical obstacle of high ignition difficulty of the inferior coal can be broken through, and the effective ignition can be realized even aiming at the inferior coal.
In the related art, the aforementioned partition plate 22 eccentrically disposed downward, the first sleeve 32 for local reinforcement, and the second sleeve 33 for amplification are not provided in the pulverized coal burner at the same time.
And this application will be down eccentric settings's baffle 22, play the first sleeve 32 of local strengthening effect and play the second sleeve 33 integration of enlarged effect in the pulverized coal burner, make the three can with enrichment facility 1 and ignition source 31 coupling, and can intercoupling between the three, with three's advantage full play, realize easy ignition, the stable and safe bias combustion process of flame propagation, make combustion process intensity higher, stability is stronger, the security is higher, effectively promote the ignition performance of pulverized coal burner.
During the operation, the primary air powder passes through the concentration device 1 and is divided into two parts, namely, thick powder and thin powder, the thick powder and the thin powder flow to the combustion area 23 and the cooling area 24 respectively after flowing out from the concentration device 1, and because the flow area of the combustion area 23 is larger than that of the cooling area 24, after the thick powder and the thin powder respectively enter the combustion area 23 and the cooling area 24, high-concentration and low-flow-rate pulverized coal airflow and low-concentration and high-flow-rate pulverized coal airflow are formed in the combustion area 23 and the cooling area 24 respectively, wherein the high-concentration and low-flow-rate pulverized coal airflow in the combustion area 23 has a small part entering a gap between the first sleeve 32 and the ignition source 31, and a small amount of high-concentration and low-flow-rate pulverized coal airflow is formed at the ignition position and is effectively ignited by the ignition source 31 to cultivate and form strong and stable initial flame, and continuously flows backwards to enter the second sleeve 33 to ignite more thick powder, the flame is stronger, the propagation is more stable, the dense 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, and the ignition capability is stronger; and the low-concentration and high-flow-rate pulverized coal airflow in the cooling zone 24 does not burn, but cools the combustion zone 23, so that the combustion zone 23 is prevented from coking, and the combustion process is safer.
It can be seen that the offset partition plate 22, the first sleeve 32 and the second sleeve 33 are coupled with the concentration device 1, the cylinder 21 and the ignition source 31, so that the combustion performance of the pulverized coal burner can be effectively improved, and the ignition capability of the pulverized coal burner on the low-quality coal can be further improved.
Here, the number of the second sleeves 33, which serve to amplify flame and stabilize combustion, is not limited to one. For example, referring to fig. 1 to 3, in some embodiments, the ignition device 3 includes at least two second sleeves 33, the at least two second sleeves 33 are sequentially sleeved from inside to outside, and the at least two second sleeves 33 are arranged in a staggered manner along the flow direction of the pulverized coal. The term "staggered arrangement in the flow direction of pulverized coal" means that two adjacent second sleeves 33 partially overlap with each other in the flow direction of pulverized coal, and in this case, in two adjacent second sleeves 33, the inlet of the second sleeve 33 located at the rear is located between the inlet and the outlet of the second sleeve 33 located at the front in the flow direction of pulverized coal, and the outlet of the second sleeve 33 located at the rear is located downstream of the outlet of the second sleeve 33 located at the front in the flow direction of pulverized coal.
Since each second sleeve 33 may form a one-stage amplification means, when at least two second sleeves 33 are provided, the offset pulverized coal burner 10 has at least two-stage amplification means, which can amplify flames step by step, stabilize combustion, and more effectively improve ignition capability.
In addition, referring to fig. 4, in some embodiments, the flow area of the second sleeve 33 is gradually increased along the flow direction of the pulverized coal. By providing the second sleeve 33 with a gradually increasing flow area along the direction of flow of the pulverized coal, the flow velocity of the pulverized coal can be gradually reduced while flowing through the second sleeve 33, which facilitates more sufficient combustion of the pulverized coal, thereby facilitating further improvement of the ignition capability of the offset pulverized coal burner 10.
The embodiments shown in fig. 1-8 are further described below.
First, a first embodiment shown in fig. 1 will be described.
As shown in fig. 1, in this first embodiment, the offset pulverized coal burner 10 includes a thickening apparatus 1, a combustion apparatus 2, and an ignition apparatus 3.
The concentration device 1 is an elbow type concentration device, and comprises an elbow pipe 11, wherein the elbow pipe 11 is used for carrying out concentration separation on coal powder by centrifugal action. Inside the elbow pipe 11, a radially outer portion serves as a dense phase zone 14, and a radially inner portion serves as a dilute phase zone 15, through which dense powder and dilute powder flow, respectively. The cross section of the elbow pipe 11 may be circular or square.
The combustion apparatus 2 includes a cylinder 21 and a partition 22. The inlet of the cylinder 21 is in direct communication with the outlet of the elbow 11. The cross section of the cylinder 21 may be circular or square. The partition plate 22 is a plate-like structure extending in the flow direction of the pulverized coal, is disposed in the cylinder 21, and is offset downward with respect to the center of the cylinder 21. The head end of the partition 22 is flush with the inlet of the cylinder 21. A space is arranged between the tail end of the partition plate 22 and the outlet of the cylinder 21. Thus, the space between the partition 22 and the portion of the side wall of the barrel 21 above the partition 22 forms a combustion zone 23, the space between the partition 22 and the portion of the side wall of the barrel 21 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 barrel 21 forms a mixing zone 25. Thus, the combustion zone 23 is opposite to the cooling zone 24 up and down and is respectively positioned above and below the partition plate 22, and the flow area of the combustion zone 23 is larger than that of the cooling zone 24; and a mixing zone 25 is located downstream of the partition 22 and communicates the outlet of the combustion zone 23 with the outlet of the cooling zone 24.
As can be seen in fig. 1, in this embodiment, the partition 22 comprises a first plate section 221 and a second plate section 222. The first plate section 221 and the second plate section 222 are sequentially connected along the flow direction of the pulverized coal. Wherein the head end of the first plate section 221 constitutes the head end of the partition 22, flush with the inlet of the cylinder 21. The rear end of the second plate section 222 forms the rear end of the partition 22 and is spaced from the outlet of the barrel 21. The tail end of the first plate section 221 is connected with the head end of the second plate section 222 in a vertically rotatable manner, so that the rotatable connection between the first plate section 221 and the second plate section 222 is realized, the first plate section 221 can change the inlet angle of the partition plate 22 by vertically rotating relative to the second plate section 222, and further change the ratio of the flow areas of the combustion zone 23 and the cooling zone 24, so as to change the proportion of pulverized coal in the combustion zone 23 and the cooling zone 24, and adapt to different media and ignition conditions more flexibly.
Specifically, as indicated by the two dashed lines in fig. 1, in this embodiment, the first plate section 221 rotates within ± 30 ° with respect to the second plate section 222. When the first plate section 221 rotates to form an angle of 0 ° with the second plate section 222, the first plate section 221 and the second plate section 222 are collinear in direction and both parallel to the longitudinal center line of the cylinder 21, and at this time, the inlet angle of the partition 22 is 0 °. When the first plate section 221 rotates to form an angle of +30 ° with the second plate section 222, the first plate section 221 is inclined upward relative to the second plate section 222 (see the upper dotted line in fig. 1), and at this time, the angle formed between the first plate section 221 and the longitudinal center line of the cylinder 21 is +30 °, and the inlet angle of the partition plate 22 is greater than 0 ° and 30 °. When the first plate section 221 is rotated to an angle of-30 ° with the second plate section 222, the first plate section 221 is inclined downward with respect to the second plate section 222 (see the lower dotted line in fig. 1), and at this time, the angle between the first plate section 221 and the longitudinal centerline of the cylinder 21 is-30 °, and the inlet angle of the partition plate 22 is less than 0 ° and-30 °.
The ignition device 3 comprises an ignition source 31, a first sleeve 32 and two second sleeves 33. Ignition source 31 is inserted into combustion region 23. The angle between ignition source 31 and the longitudinal centerline of barrel 21 may be 0-90 ° during insertion, i.e., ignition source 31 may be inserted horizontally, vertically or obliquely into combustion zone 23, and may be specifically adjusted according to the field installation space and factors such as ignition effect and ignition safety. The first sleeve 32 and the two second sleeves 33 are both provided in the cylinder 21. The first sleeve 32 is sleeved outside the ignition source 31, and a gap between the first sleeve and the ignition source 31 is 1-15mm, so that a local strengthening effect is achieved, and the cultivation of initial flame is facilitated. The two second sleeves 33 are respectively referred to as a first amplification cylinder and a second amplification cylinder, wherein the first amplification cylinder is sleeved outside the first sleeve 32 and partially overlaps the first sleeve 32 in the flow direction of the pulverized coal; the second amplification cylinder is sleeved outside the first amplification cylinder and partially overlaps the second amplification cylinder in the flow direction of the pulverized coal. The first amplification cylinder and the second amplification cylinder amplify the flame step by step together.
As can be seen from fig. 1, in the first embodiment, the first sleeve 32 and each of the second sleeves 33 are in a straight cylindrical shape. It should be noted that the shapes of the first sleeve 32 and the second sleeve 33 are not limited thereto, as will be apparent from the embodiments shown in fig. 2 to 4.
The offset pulverized coal burner 10 of the embodiment can make the dense powder and the weak powder respectively and directly enter the combustion area 23 with a large flow area and the cooling area 24 with a small flow area on the basis of separating the dense powder and the weak powder by the bent pipe 11, respectively form a low-speed but high-concentration atmosphere and a high-speed but low-concentration atmosphere in the combustion area 23 and the cooling area 24, respectively, and an ignition source 31 effectively ignites a small part of the dense powder entering the combustion area 23 under the protection of the first sleeve 32, and then the dense powder is gradually combusted in the combustion area 23 by matching with the gradual amplification action of the two second sleeves 33, and the weak powder in the cooling area 24 can play a certain cooling role to prevent coking, and then the pulverized coal airflows flowing out from the combustion area 23 and the cooling area 24 are mixed in the mixing area 25 to further cool and intensify the combustion, and finally out of the outlet of the cylinder 21. In the whole process, the ignition is easy, the combustion is stable, and the burning loss and coking are not easy to occur, so that the offset pulverized coal burner 10 has better ignition performance for the low-quality coal and the high-moisture coal, and can realize the effective ignition of the low-quality coal and the high-moisture coal.
Other embodiments shown in fig. 2-8 are described next. When other embodiments are introduced, only differences from the embodiments are focused on for simplicity of description, and the like are not excessively introduced.
First, a second embodiment shown in fig. 2 will be described.
As shown in fig. 2, the second embodiment differs from the first embodiment mainly in the shape of the first sleeve 32.
Specifically, as shown in fig. 2, in this second embodiment, the first sleeve 32 is no longer straight cylindrical but is tapered cylindrical.
More specifically, as can be seen from fig. 2, in this second embodiment, the first sleeve 32 has a diverging conical-cylindrical structure. At this time, the flow area of the first sleeve 32 gradually increases along the flow direction of the pulverized coal, so that the pulverized coal can be decelerated more effectively to further reduce the difficulty of ignition.
In addition, this second exemplary embodiment differs from the first exemplary embodiment in that the rotation range of the first plate section 221 relative to the second plate section 222 is no longer ± 30 °, but ± 20 °, i.e., the first plate section 221 is rotated relative to the second plate section 222 within ± 20 °. Thus, the eddy current can be reduced on the basis of meeting the ignition performance.
Next, a third embodiment shown in fig. 3 will be described.
As shown in fig. 3, this third embodiment differs from the first and second embodiments mainly in that the first sleeve 32 is no longer in a straight or tapered cylindrical shape, but rather in a drum shape.
Next, a fourth embodiment shown in fig. 4 will be described.
As shown in fig. 4, the fourth embodiment is different from the first embodiment mainly in the number and shape of the second sleeves 33. Specifically, as shown in fig. 4, in this fourth 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 becomes larger in the flow direction of the pulverized coal. More specifically, as can be seen from fig. 4, in this fourth embodiment, the second sleeve 33 has a tapered cylindrical shape that is divergent in the flow direction of the pulverized coal.
Because the flow area of the second sleeve 33 is gradually increased along the flow direction of the pulverized coal, the second sleeve 33 can more effectively decelerate the pulverized coal to achieve more sufficient and stable combustion of the pulverized coal in the combustion zone 23.
It is understood that, in order to further improve the combustion performance by decelerating the pulverized coal, in this fourth embodiment, the first sleeve 32 may also be provided such that the flow area becomes gradually larger in the flow direction of the pulverized coal.
Next, a fifth embodiment shown in fig. 5 will be described.
As shown in fig. 5, the fifth embodiment is different from the four embodiments mainly in the structure of the cylinder 21.
As shown in fig. 5, in this fifth embodiment, the cylinder 21 is not entirely of a uniform cross-sectional structure but includes a variable cross-sectional portion. In particular, as can be seen from fig. 5, in this fifth embodiment, the cylinder 21 comprises a first cylinder section 211 and a second cylinder section 212. The first barrel section 211 connects the thickening apparatus 1 and the second barrel section 212. Along the flow direction of the pulverized coal, the flow area of the first cylindrical section 211 is gradually increased; the flow area of the second cylindrical section 212 is equal everywhere and still has a uniform cross-sectional structure.
The flow area of the first cylinder section 211 gradually increases along the flowing direction of the pulverized coal, so that the inlet section of the cylinder 21 forms a slope section, which not only can realize the transition between the elbow 11 with different diameters and the second cylinder section 212, but also is beneficial to reducing the vortex and the accumulated powder when the pulverized coal flows.
Next, a sixth embodiment shown in fig. 6 will be described.
In fig. 6, the ignition source 31 is not shown, but rather a flame is schematically shown in a corresponding position.
As shown in fig. 6, this sixth embodiment differs from the first embodiment mainly in that, on the one hand, the number of second sleeves 33 is no longer two, but only one; on the other hand, the mixing zone 25 is no longer of constant cross-section, but comprises a tapered section 251. The flow area of the tapered section 251 gradually decreases along the flow direction of the pulverized coal. Specifically, the tapered section 251 has a tapered shape that tapers along the flow direction of the pulverized coal. Also, as can be seen in fig. 6, in this embodiment, the mixing zone 25 further comprises a constant cross-section connected to the end of the tapered section 251.
The tapered section 251 can guide the two parts of pulverized coal flowing out from the combustion zone 23 and the cooling zone 24 to be mixed more sufficiently and rapidly, so that the rectification effect is achieved, the turbulence is reduced, and the acceleration of the pulverized coal injection flow speed is facilitated.
Next, a seventh embodiment shown in fig. 7 will be described.
In fig. 7, like in fig. 6, the ignition source 31 is also not shown, but the flame is schematically shown in the corresponding position.
As shown in fig. 7, the seventh embodiment differs from the first embodiment in the number of second sleeves 33, another major difference being the construction of the thickening apparatus 1. The differences of the concentrator 1 will be mainly described here.
As can be seen from fig. 7, in this seventh embodiment, the concentrator 1 includes not only the elbow 11, but also the bending plate 12 and the stopper 13. The bent plate 12 is disposed in the bent tube 11 and extends along a longitudinal center line of the bent tube 11, at this time, a direction of the bent plate 12 is the same as a direction of the bent tube 11, and the dense phase zone 14 and the dilute phase zone 15 are respectively located on a radial outer side and a radial inner side of the bent plate 12, that is, the bent plate 12 divides a tube cavity of the bent tube 11 into the dense phase zone 14 located on the radial outer side of the bent plate 12 and the dilute phase zone 15 located on the radial inner side of the bent plate 12. The trailing end of the bent plate 12 is located above the partition 22, i.e. the trailing end of the bent plate 12 is located within the combustion zone 23. The stopper 13 is provided on the inner surface of the side wall of the elbow pipe 11 on the radially outer side.
Fig. 7 schematically shows the flow of pulverized coal in the case where the bent plate 12 and the stopper 13 are provided.
Referring to fig. 7, the curved plate 12 and the stopper 13 can guide the pulverized coal to converge toward the curved plate 12, so as to improve the concentration of the concentrated pulverized coal toward the combustion region 23, effectively enhance the separation, concentration and drainage effects, and further improve the ignition and stable combustion performance of the offset pulverized coal burner 10.
It is understood that the thickening effect can be improved to some extent also when only one of the bent plate 12 and the stopper 13 is provided in the bent pipe 11, as compared with the case where the thickening apparatus 1 includes only the bent pipe 11.
In fig. 7, the bending plate 12 is disposed concentrically with the bent pipe 11 in the bent pipe 11, that is, the bending plate 12 is located on the longitudinal center line of the bent pipe 11. However, in the embodiment not shown, the bent plate 12 may be eccentrically disposed in the elbow pipe 11 toward the radially outer side, that is, the bent plate 12 may be located radially outward of the longitudinal centerline of the elbow pipe 11.
The bent plate 12 is arranged to be eccentric towards the radial outer side relative to the bent pipe 11, so that more pulverized coal can be guided to flow into the combustion zone 23, and better concentration and flow guiding effects can be realized.
The cross-sectional form of the flexural plate 12 can vary. Several of which are shown in fig. 10-14.
In fig. 10, the bent plate 12 has a rectangular cross section. The bent plate 12 at this time may be referred to as a straight deflector or a straight bent plate.
In fig. 11, the bent plate 12 has an arc-shaped cross section. The bent plate 12 at this time may be referred to as an arc deflector or an arc bent plate.
In fig. 12, the bent plate 12 has a V-shaped cross section. Specifically, the bent plate 12 includes a first plate portion 121 and a second plate portion 122. The first plate portion 121 and the second plate portion 122 are connected to each other at an angle such that the connection therebetween forms a V-shape. The bent plate 12 at this time may be referred to as a V-shaped baffle or a V-shaped bent plate. The V-shaped guide plate can enhance the concentration effect of the pulverized coal airflow in the center of the bent plate 12. Meanwhile, the V-shaped expansion angle can be flexibly designed to adapt to different installation occasions.
In fig. 13, the bent plate 12 has a double V-shape in cross section. Specifically, the bent plate 12 includes a first plate portion 121, a second plate portion 122, a third plate portion 123 and a fourth plate portion 124, the first plate portion 121, the second plate portion 122, the third plate portion 123 and the fourth plate portion 124 are connected in sequence, and the first plate portion 121 and the second plate portion 122, the second plate portion 122 and the third plate portion 123 and the fourth plate portion 124 are connected at an angle, that is, all connected to form a V shape. The bent plate 12 at this time may be referred to as a double V-shaped baffle or a double V-shaped bent plate. The double V-shaped guide plates are beneficial to realizing better concentration effect.
In fig. 14, the flexural plate 12 is a torsion plate. Specifically, the bent plate 12 includes a first plate portion 121 and a second plate portion 122, the first plate portion 121 and the second plate portion 122 are connected to each other, and the first plate portion 121 and the second plate portion 122 are twisted relatively. The flexural plate 12 at this point may be referred to as a torsional deflector or a torsional flexural plate. The twisted guide plate can be obtained by twisting a certain angle on the basis of the V-shaped guide plate shown in fig. 12, which is beneficial to breaking the limitation that the pulverized coal burner can only be horizontally or vertically installed while ensuring the pulverized coal concentration effect, and effectively improving the flexibility of the field installation angle of the offset pulverized coal burner 10.
In the design and application process of the offset pulverized coal burner 10, different types of bent plates 12 can be selected according to different boiler types, medium types, customary operation conditions and other conditions, so as to better organize pulverized coal airflow, realize effective concentration of the pulverized coal airflow and fully guide the pulverized coal to the combustion area 23.
Turning next to fig. 8, an eighth embodiment shown in fig. 8 will be described.
As shown in fig. 8, the eighth embodiment is different from the previous embodiments mainly in that the concentration device 1 is not an elbow type concentration device, but a block type concentration device. Specifically, as shown in fig. 8, in this embodiment, the concentration device 1 does not include the bent pipe 11 any more, but includes the straight pipe 16, and the stopper 13 is provided in the straight pipe 16. The stopper 13 is provided on the inner surface of the bottom wall of the straight tube 16. At this time, the stopper 13 guides the pulverized coal to be accumulated toward the upper portion so that the concentrated pulverized coal enters the combustion zone 23.
In addition, as can be seen from fig. 8, in the eighth embodiment, similar to the fifth embodiment shown in fig. 5, the cylindrical body 21 also includes the first cylindrical section 211 whose flow area gradually increases along the flow direction of the pulverized coal, but unlike the fifth embodiment, the first cylindrical section 211 is not inclined outward at the side walls located at the upper and lower sides of the partition 22, but is inclined outward only at the side wall located at the upper side of the partition 22, and the side wall located at the lower side of the partition 22 of the first cylindrical section 211 still extends horizontally.
In the foregoing embodiments, the partition 22 may be a flat plate or a curved plate. For example, referring to FIG. 9, in some embodiments, the partition 22 is an arcuate plate having a curved cross-section, with the partition 22 being concave downward.
Compared with the condition that the partition plate 22 is a flat plate, when the partition plate 22 is an arc-shaped plate, the transition of the joint of the two ends of the partition plate 22 and the side wall of the cylinder 21 is smooth, the resistance is small, the flow field can be smoother, the low-speed area and the powder accumulation phenomenon at the side wall can be avoided, and the ignition safety can be improved.
In addition, under the condition that the partition plate 22 is offset and the cross section of the cylinder 21 is circular, if the partition plate 22 is a flat plate, the top wall of the combustion region 23 is the side wall of the cylinder 21 and is arc-shaped, and the bottom wall of the combustion region 23 is the partition plate 22 and is a straight plate, at this time, the combustion region 23 is asymmetric up and down, and the offset ignition source 31 positioned at the center of the combustion region 23 deviates from the integral center of the offset pulverized coal burner 10 farther, which is unfavorable for the uniformity of combustion, and is easy to cause flame to brush the wall, thus causing the coking problem; when the partition plate 22 is an arc-shaped plate, as shown in fig. 9, the top wall and the bottom wall of the combustion zone 23 are both arc-shaped, which is beneficial to the smooth and symmetrical distribution in the combustion zone 23, in this case, not only can the advantage of offset of the ignition center be retained, but also the offset of the offset ignition center can be relatively close to the overall center of the pulverized coal burner 10, thereby reducing the risk of coking.
Meanwhile, with continued reference to fig. 9, in some embodiments, the outlet of the barrel 21 is circular, which facilitates the cooperation with the boiler windbox, so that the offset pulverized coal burner 10 can be flexibly installed for the field situation, and has good field adaptability.
In summary, the offset pulverized coal burner 10 provided by the embodiment of the invention has the advantages of simple structure and excellent combustion performance, and is beneficial to solving the problems of ignition and stable combustion of poor-quality coal, high-moisture coal and other poor-quality coal.
The offset pulverized coal burner 10 provided by the embodiment of the invention is applied to a combustion system, so that the performance of the combustion system can be effectively improved. Accordingly, embodiments of the present invention also provide a combustion system that includes a boiler and the offset pulverized coal burner 10 of the various embodiments of the present invention.
The above description is only exemplary of the present invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (20)
1. An offset pulverized coal burner (10), comprising:
the concentration device (1) is used for separating the coal powder into thick powder and light powder;
the combustion device (2) comprises a cylinder (21) and a partition plate (22), wherein an inlet of the cylinder (21) is communicated with an outlet of the concentration device (1), the partition plate (22) is eccentrically arranged in the cylinder (21) downwards and divides the inner space of the cylinder (21) into a combustion area (23) and a cooling area (24), the combustion area (23) is positioned above the partition plate (22) and used for receiving the concentrated powder, the cooling area (24) is positioned below the partition plate (22) and used for receiving the diluted powder, a mixing area (25) is further arranged in the cylinder (21), the mixing area (25) is positioned at the downstream of the partition plate (22) along the flow direction of the pulverized coal and is communicated with both the outlet of the combustion area (23) and the outlet of the cooling area (24); and
-an ignition device (3) comprising an ignition source (31), said ignition source (31) being inserted in said combustion zone (23).
2. The offset pulverized coal burner (10) as claimed in claim 1, characterized in that the mixing zone (25) comprises a tapered section (251), the flow area of the tapered section (251) decreasing gradually in the pulverized coal flow direction.
3. The offset pulverized coal burner (10) as claimed in claim 1, characterized in that the baffle plate (22) comprises a first plate section (221) and a second plate section (222), the first plate section (221) and the second plate section (222) are arranged in sequence along the pulverized coal flow direction, and the first plate section (221) is connected with the second plate section (222) in a manner of being capable of rotating up and down so as to change the flow area ratio of the combustion zone (23) and the cooling zone (24).
4. The offset pulverized coal burner (10) as claimed in claim 3, characterized in that the first plate section (221) is rotated within a range of ± 30 ° with respect to the second plate section (222).
5. The offset pulverized coal burner (10) as claimed in claim 1, characterized in that the partition (22) is adjustable in length.
6. The offset pulverized coal burner (10) as claimed in any of claims 1 to 5, characterized in that the length of the mixing zone (25) is 20 to 90% of the total length of the barrel (21).
7. The offset pulverized coal burner (10) as claimed in any one of claims 1 to 5, wherein said ignition source (31) is located in the center of said combustion zone (23).
8. The offset pulverized coal burner (10) as claimed in any one of claims 1 to 5, characterized in that the cross section of the baffle plate (22) is a cambered surface.
9. The offset pulverized coal burner (10) as claimed in any one of claims 1 to 5, characterized in that said ignition device (3) further comprises a first sleeve (32), said first sleeve (32) being disposed within said combustion zone (23) and being sleeved outside said ignition source (31).
10. The offset pulverized coal burner (10) as claimed in claim 9, characterized in that the gap between the first sleeve (32) and the ignition source (31) is 1-15 mm.
11. The offset pulverized coal burner (10) as claimed in claim 9, characterized in that the ignition device (3) further comprises a second sleeve (33) disposed in the combustion zone (23), the second sleeve (33) being sleeved outside the first sleeve (32) and being arranged offset from the first sleeve (31) in the flow direction of the pulverized coal.
12. The offset pulverized coal burner (10) as claimed in claim 11, characterized in that the ignition device (3) comprises at least two second sleeves (33), the at least two second sleeves (33) are sequentially sleeved from inside to outside, and the at least two second sleeves (33) are arranged in a staggered manner along the flow direction of pulverized coal.
13. The offset pulverized coal burner (10) as claimed in claim 11, characterized in that the flow area of the second sleeve (33) is gradually increased in the pulverized coal flow direction.
14. The offset pulverized coal burner (10) as claimed in any of claims 1 to 5, characterized in that the inlet of the barrel (21) is in direct communication with the outlet of the thickening apparatus (1).
15. The offset pulverized coal burner (10) as claimed in any one of claims 1 to 5, wherein the barrel (21) comprises a first barrel section (211) and a second barrel section (212), the first barrel section (211) connects the concentrator (1) and the second barrel section (212), and the flow area of the first barrel section (211) increases gradually along the pulverized coal flow direction.
16. The offset pulverized coal burner (10) as claimed in any of claims 1 to 5, characterized in that the flow area of the combustion zone (23) is larger than the flow area of the inlet of the thickening apparatus (1).
17. The offset pulverized coal burner (10) as claimed in any of claims 1 to 5, characterized in that the concentrator device (1) comprises an elbow (11), the inlet and outlet of the elbow (11) forming the inlet and outlet, respectively, of the concentrator device (1), and in that the concentrator device (1) further comprises:
a bent plate (12) disposed within the bent pipe (11) and extending along a longitudinal centerline of the bent pipe (11); and/or the presence of a gas in the gas,
and a stopper (13) provided on an inner surface of a radially outer side wall of the elbow pipe (11).
18. The offset pulverized coal burner (10) as claimed in claim 17, characterized in that the bent plate (12) is eccentrically arranged in the bent tube (11) towards the radial outside.
19. The offset pulverized coal burner (10) as claimed in claim 18, characterized in that the cross-section of the bent plate (12) is rectangular, curved, V-shaped or double V-shaped, or the bent plate (12) is a twisted plate.
20. A combustion system comprising a boiler, characterized by further comprising an offset pulverized coal burner (10) as claimed in any one of claims 1 to 19, the outlet of said barrel (21) communicating with the interior of said boiler.
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CN112781033A (en) * | 2021-03-18 | 2021-05-11 | 烟台龙源电力技术股份有限公司 | Offset pulverized coal burner and combustion system |
CN112781034A (en) * | 2021-03-18 | 2021-05-11 | 烟台龙源电力技术股份有限公司 | Offset pulverized coal burner and combustion system |
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