Pulverized coal airflow separation and redistribution device and medium-speed coal mill

Abstract

The invention relates to a pulverized coal airflow separation and redistribution device and a medium-speed coal mill. The pulverized coal airflow separation and redistribution device comprises an elbow pipe, a separation shell, a rotary body and a driving part, one end of the elbow pipe is arranged at an outlet of a separator of the medium-speed coal mill, the other end of the elbow pipe forms a dilute-phase area in the area of the inner side of the elbow pipe, the other end of the elbow pipe forms a dense-phase area in the area of the outer side of the elbow pipe, the separation shell is communicated with the elbow pipe, and the rotary body is arranged in the separation shell. One side of the separation shell is used for being communicated with a separator of the medium-speed coal mill, the rotary body is rotatably arranged on the other side of the separation shell and is opposite to the concentrated phase area, the inner side and the outer side of the rotary body are communicated in the radial direction of the rotary body, a channel of the rotary body is used for being communicated with a primary air powder pipe, and the driving part is connected with the rotary body to drive the rotary body to rotate. According to the pulverized coal airflow separation and redistribution device, pulverized coal airflow of the primary pulverized coal pipes is adjusted, and the pulverized coal airflow of the multiple primary pulverized coal pipes of the medium-speed coal mill is adjusted, so that uniform distribution of pulverized coal among the outlets is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas-solid two-phase flow conveying of coal-fired boilers, and particularly relates to a coal powder gas flow separation and redistribution device and a medium-speed coal mill. BACKGROUND

[0002] Generally, a medium-speed mill direct-fired pulverizing system is adopted in a large power station coal-fired boiler. Compared with a warehouse-type pulverizing system, primary air powder in each coal powder pipe at the outlet of the medium-speed coal mill is directly supplied to each burner in real time, and whether the distribution of the coal powder amount and the air amount in each coal powder pipe at the outlet of the mill is uniform directly affects the combustion intensity distribution in the furnace. Under the background that coal-fired units generally participate in deep load regulation, only by improving the uniformity of the air powder distribution at the outlet of each burner in the furnace, can the operation safety of the unit be ensured under deep load regulation, while the environmental protection, economy and flexibility are still taken into account. However, as a device for solving the above problems, the coal powder distributor has developed various styles after years of technical iteration, but all of them are large in size and high in requirement for the site reconstruction space, which limits the popularization and application thereof on the existing units. SUMMARY

[0003] The present application aims to at least solve one of the technical problems in the related art to some extent.

[0004] To this end, an embodiment of the present application provides a coal powder gas flow separation and redistribution device, which is small in size, simple in structure, low in requirement for the reconstruction space of the existing medium-speed coal mill, and convenient to install on the existing unit of the medium-speed coal mill. By adjusting the coal powder gas flow of a plurality of primary air powder pipes of the medium-speed coal mill, uniform distribution of the air powder among the outlets (outlets of the primary air powder pipes) is realized.

[0005] An embodiment of the present application provides a medium-speed coal mill.

[0006] The coal powder gas flow separation and redistribution device according to the embodiment of the present application comprises a bend-through pipe, a separation shell, a rotary body and a driving member. One end of the bend-through pipe is arranged at the outlet of a separator of the medium-speed coal mill. A dilute phase zone is formed in the area on the inner side or adjacent to the inner side of the other end of the bend-through pipe. A dense phase zone is formed in the area on the outer side or adjacent to the outer side of the other end of the bend-through pipe. The separation shell is in communication with the bend-through pipe. One side of the separation shell is arranged in communication with the separator of the medium-speed coal mill. The rotary body is rotatably arranged on the other side of the separation shell. The rotary body is opposite to the dense phase zone. The rotary body comprises a channel. The inner side and the outer side of the rotary body are in communication in the radial direction of the rotary body. The channel of the rotary body is arranged in communication with a primary air powder pipe. The driving member is connected with the rotary body to drive the rotary body to rotate.

[0007] The coal powder airflow separation and redistribution device of the embodiment of the present application is installed between the primary air powder pipe and the separator, separates part of the coal powder particles in the dense phase coal powder airflow, and sends them back to the separator for redistribution, thereby adjusting the coal powder airflow of the primary air powder pipe, and adjusting the coal powder airflow of multiple primary air powder pipes of the medium-speed coal mill, and realizing uniform distribution of the air and powder among the outlets (outlets of the primary air powder pipes).

[0008] In some embodiments, the rotary body comprises a connecting pipe and multiple baffles, the connecting pipe is rotatably arranged at the other side of the separation shell, the driving member is connected with the connecting pipe, the connecting pipe forms the channel, one end of the connecting pipe is used for communicating with the primary air powder pipe, the other end of the connecting pipe is opposite to the dense phase zone, the other end of the connecting pipe is open, the other end of the connecting pipe is provided with multiple communication holes distributed along the circumference thereof, and the baffles are arranged at one side of the connecting pipe at the communication holes.

[0009] In some embodiments, the coal powder airflow separation and redistribution device further comprises dynamic and static ring-shaped sealing members, and the dynamic and static ring-shaped sealing members are arranged between the rotary body and the separation shell and between the rotary body and the primary air powder pipe.

[0010] In some embodiments, the coal powder airflow separation and redistribution device further comprises a partition plate, the partition plate is arranged in the other end of the elbow pipe, and the partition plate separates the dense phase zone and the dilute phase zone.

[0011] In some embodiments, the elbow pipe comprises an arc-shaped section and a separation section, one end of the arc-shaped section is used for being arranged at the outlet of the medium-speed coal mill separator, the other end of the elbow pipe is connected with the separation section, the separation section is tangent to the arc-shaped section, the separation shell communicates with the separation section, and the separation section is provided with the partition plate.

[0012] In some embodiments, the separation shell comprises a ring-shaped shell and a conical shell, the ring-shaped shell is located at the other side of the separation shell, the conical shell is located at the one side of the separation shell, the conical shell comprises a large-diameter end and a small-diameter end, the large-diameter end communicates with the ring-shaped shell, and the small-diameter end is used for communicating with the medium-speed coal mill separator.

[0013] In some embodiments, the coal powder airflow separation and redistribution device further comprises a return powder pipe and a gas locking plate, one end of the return powder pipe communicates with the one side of the separation shell, the other end of the return powder pipe is used for communicating with the medium-speed coal mill separator, and the gas locking plate is arranged in the return powder pipe.

[0014] In some embodiments, the other end of the return duct is located at the edge of the medium-speed coal mill separator, and the other end of the return duct is spaced apart from the outlet of the medium-speed coal mill separator.

[0015] In some embodiments, the driving member is a variable frequency driving device.

[0016] The medium-speed coal mill of the embodiment of the present application comprises a separator, a pulverized coal gas flow separation and redistribution device and a primary air duct, one end of the arc segment of the elbow duct is arranged at the outlet of the separator, one side of the separation shell is communicated with the separator, and the rotary body is communicated with the primary air duct. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Fig. 1 is a structural schematic diagram of the medium-speed coal mill of the embodiment of the present application.

[0018] REFERENCE NUMERALS 100, redistribution device; 1, elbow duct, 11, arc segment, 12, partition segment; 2, separation shell, 21, annular shell, 22, conical shell; 3, rotary body, 31, connecting pipe, 32, baffle; 4, driving member; 5, dynamic and static ring-shaped sealing member; 6, partition plate; 7, return duct; 8, air locking plate; 200, separator; 300, primary air duct. DETAILED DESCRIPTION

[0019] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0020] The pulverized coal gas flow separation and redistribution device 100 and the medium-speed coal mill of the embodiment of the present application are described in detail below with reference to the accompanying drawings.

[0021] Referring to Figure 1 , the medium-speed coal mill of the embodiment of the present application comprises a separator 200, a pulverized coal gas flow separation and redistribution device 100 and a primary air duct 300.

[0022] The coal powder airflow separation and redistribution device 100 of the embodiment of the present application comprises a bend pipe 1, a separation shell 2, a rotary body 3 and a driving member 4. One end of the bend pipe 1 is arranged at the outlet of the medium-speed coal mill separator 200, the other end of the bend pipe 1 forms a dilute phase zone at the inner side or the region adjacent to the inner side of the other end of the bend pipe 1, and the other end of the bend pipe 1 forms a dense phase zone at the outer side or the region adjacent to the outer side of the other end of the bend pipe 1. The separation shell 2 is in communication with the bend pipe 1, and one side of the separation shell 2 is in communication with the medium-speed coal mill separator 200. The rotary body 3 is rotatably arranged at the other side of the separation shell 2, the rotary body 3 is opposite to the dense phase zone, the rotary body 3 comprises a passage, the inner side and the outer side of the rotary body 3 are in communication in the radial direction of the rotary body 3, and the passage of the rotary body 3 is used for communicating the primary air powder pipe 300. The driving member 4 is connected with the rotary body 3 to drive the rotary body 3 to rotate.

[0023] As shown in the use of the medium-speed coal mill of the embodiment of the present application, Figure 1 the coal powder airflow flows out from the top of the medium-speed coal mill separator 200, and then flows through the bend pipe 1. Since the bend pipe 1 is a curved pipe, the dense and dilute separation is realized due to the difference in flow inertia of the coal powder and the gas after flowing through the bend pipe 1, and the dense phase coal powder airflow with more coal powder particles and the dilute phase coal powder airflow with less coal powder particles are formed after flowing through the bend pipe 1. The dense phase coal powder airflow is distributed at the outer arc side of the bend pipe 1 and then enters the dense phase zone, and the dilute phase coal powder airflow is distributed at the inner arc side of the bend pipe 1 and then enters the dilute phase zone. The rotary body 3 rotates around the central axis under the driving of the driving member 4. When the dense phase coal powder airflow flows through the rotary body 3, part of the coal powder particles is thrown to the inner wall of the shell of the separation shell 2 under the driving of the rotary body 3 due to the rotation inertia, slides along the wall to the bottom outlet, and then returns to the medium-speed coal mill separator 200 to participate in the redistribution of the coal powder. The other part of the dense phase coal powder airflow enters the primary air distribution pipe through the passage in the rotary body 3. The dilute phase coal powder airflow flows out of the dilute phase zone and enters the separation shell 2, and then enters the primary air powder pipe 300 from the bottom inlet of the hollow flow channel in the rotary body 3.

[0024] The coal powder airflow separation and redistribution device 100 of the embodiment of the present application is installed between the primary air powder pipe 300 and the separator 200. The coal powder airflow separation and redistribution device 100 separates part of the coal powder particles in the dense phase coal powder airflow and sends them back to the separator 200 for redistribution, adjusts the coal powder airflow of the primary air powder pipe 300, and adjusts the coal powder airflow of the multiple primary air powder pipes 300 of the medium-speed coal mill to realize the uniform distribution of the air and powder among the outlets (the outlets of the primary air powder pipes 300).

[0025] In addition, the coal powder airflow separation and redistribution device 100 of the embodiment of the present application has a small volume and a simple structure, has a low requirement on the transformation space of the existing medium-speed coal mill, and is convenient to install on the existing medium-speed coal mill unit.

[0026] In some embodiments, the coal powder airflow separation and redistribution device 100 further comprises a partition plate 6 arranged in the other end of the elbow pipe 1, the partition plate 6 separates the dense phase region and the dilute phase region. The partition plate 6 separates the space of the other end of the elbow pipe 1, so that the dense phase region and the dilute phase region are separated, thereby ensuring the stability of the dense phase coal powder airflow flowing from the dense phase region to the rotary body 3, ensuring the separation effect of the rotary body 3 on the dense phase coal powder airflow, and further ensuring the uniform distribution of the air-powder in each primary air-powder pipe 300.

[0027] In some embodiments, the elbow pipe 1 comprises an arc segment 11 and a separation segment 12, one end (lower end) of the arc segment 11 is arranged at the outlet of the medium-speed coal mill separator 200, the other end (upper end) of the elbow pipe 1 is connected with the separation segment 12, the separation segment 12 is tangent to the arc segment 11, the separation shell 2 is communicated with the separation segment 12, and the partition plate 6 is arranged in the separation segment 12. The separation segment 12 is a straight pipe, and the arc segment 11 is an arc pipe. The separation segment 12 is tangent to the arc segment 11, which not only facilitates the arrangement of the partition plate 6 in the elbow pipe 1 and the connection of the elbow pipe 1 with the separation shell 2, but also has little effect on the flow path of the coal powder airflow and the distribution areas of the dense phase and the dilute phase, thereby ensuring that the coal powder airflow is separated into the dense phase coal powder airflow and the dilute phase coal powder airflow after passing through the elbow pipe 1.

[0028] Specifically, the bending angle of the arc segment 11 is 90°. The one end of the arc segment 11 is located at the outlet above the separator 200.

[0029] In some embodiments, the rotary body 3 comprises a connecting pipe 31 and a plurality of baffles 32. The connecting pipe 31 is rotatably arranged at the other side of the separation shell 2, the driving member 4 is connected with the connecting pipe 31, the connecting pipe 31 forms a passage, one end (upper end) of the connecting pipe 31 is communicated with the primary air-powder pipe 300, the other end (lower end) of the connecting pipe 31 is opposite to the dense phase region, the other end of the connecting pipe 31 is open, the other end of the connecting pipe 31 is provided with a plurality of communication holes distributed along the circumferential direction thereof, and the baffles 32 are arranged on one side of the connecting pipe 31 at the communication holes. The rotary body 3 is installed on the separation shell 2 through the connecting pipe 31, the communication holes on the connecting pipe 31 realize the communication between the inner side and the outer side of the rotary body 3 in the radial direction thereof, when the driving member 4 drives the rotary body 3 to rotate at high speed, the baffles 32 rotate at high speed, the baffles 32 rotating at high speed drive the dense phase coal powder airflow flowing through the baffles 32 to rotate, so that part of the coal powder in the dense phase coal powder airflow is thrown out of the rotary body 3 to the inner wall surface of the separation shell 2 under the action of the rotating centrifugal force, and then the coal powder falls into the separator 200 under the action of gravity.

[0030] In some embodiments, the coal powder airflow separation and redistribution device 100 further comprises dynamic and static ring-shaped sealing members 5, the dynamic and static ring-shaped sealing members 5 are arranged between the rotary body 3 and the separation shell 2 and between the rotary body 3 and the primary air-powder pipe, thereby ensuring that the positive pressure coal powder airflow located inside the separation shell 2 and the connecting pipe 31 cannot overflow outward.

[0031] In some embodiments, the driving member 4 is a variable frequency driving device. The variable frequency driving device can be remotely adjusted online in real time. By changing the operating frequency of the variable frequency driving device, the personnel can change the rotating speed of the rotating body 3. With the increase of the rotating speed of the rotating body 3, more coal particles will be separated from the dense phase coal gas flow in unit time and slide along the wall of the separation shell 2 to the bottom to return to the medium-speed mill separator 200 to participate in the coal powder redistribution. Therefore, the rotating speed of the corresponding rotating body 3 is adjusted according to the concentration of the coal gas flow flowing through the coal gas flow separation and redistribution device 100, and the amount of coal powder separated by different coal gas flow separation and redistribution devices 100 is adjusted, so as to further ensure the uniform distribution of the air and powder of each primary air and powder pipe 300.

[0032] In some embodiments, the separation shell 2 includes an annular shell 21 and a conical shell 22. The annular shell 21 is located at the other side (upper side) of the separation shell 2, and the conical shell 22 is located at one side (lower side) of the separation shell 2. Specifically, the annular shell 21 is in communication with the partition section 12, and the connecting pipe 31 of the rotating body 3 is rotatably arranged on the annular shell 21. The conical shell 22 includes a large-diameter end and a small-diameter end. The large-diameter end is in communication with the annular shell 21, and the small-diameter end is in communication with the medium-speed mill separator 200. The upper large and lower small inner cavity of the conical shell 22 guides the falling of the coal particles, facilitating the falling of the coal particles into the separator 200.

[0033] In some embodiments, the coal gas flow separation and redistribution device 100 further includes a return pipe 7 and a gas locking plate 8. One end (upper end) of the return pipe 7 is in communication with one side (lower side) of the separation shell 2, the other end (lower end) of the return pipe 7 is in communication with the medium-speed mill separator 200, and the gas locking plate 8 is arranged in the return pipe 7. The gas locking plate 8 allows the coal particles to pass through smoothly, and at the same time, tries to reduce or prevent the mutual flow of gas, so as to prevent the coal gas flow in the medium-speed mill separator 200 from flowing into the separation shell, thereby maintaining the stability of the gas flow and the pressure balance in the system.

[0034] The other end of the return pipe 7 is located at the edge of the medium-speed mill separator 200, and the other end of the return pipe 7 is spaced apart from the outlet of the medium-speed mill separator 200. The arrangement of the return pipe 7 is reasonable in layout and has low requirements for the reconstruction space.

[0035] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated thereby must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0036] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated thereby. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0037] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or in communication with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication or interaction relationship of two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0038] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0039] In this disclosure, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the present disclosure. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily referred to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, the terminology "comprising" is used in the disclosure as comprising but not limited to, that is, it is open-ended and does not exclude the presence of additional features, structures, materials, or characteristics.

[0040] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above-described embodiments are exemplary, and are not to be interpreted as limiting the present disclosure, and the ordinary skilled person in the art can make changes, modifications, replacements, and variations to the above-described embodiments within the scope of the present disclosure.

Claims

1. A pulverized coal gas flow separation and redistribution device (100), characterized in that, include: A bend (1) is provided at one end of the outlet of the medium-speed coal mill separator (200), and the other end of the bend (1) forms a dilute phase region in the region inside or near the inside, and the other end of the bend (1) forms a dense phase region in the region outside or near the outside. Separation shell (2), the separation shell (2) is connected to the bend pipe (1), and one side of the separation shell (2) is used to connect to the medium speed coal mill separator (200); A rotating body (3) is rotatably disposed on the other side of the separation shell (2), the rotating body (3) being opposite to the dense phase zone, the rotating body (3) including a channel, the inner and outer sides of the rotating body (3) being radially connected, the channel of the rotating body (3) being used to connect to the primary air-powder pipe (300); and A drive unit (4) is connected to the rotating body (3) to drive the rotating body (3) to rotate.

2. The pulverized coal gas flow separation and redistribution device (100) according to claim 1, characterized in that, The rotating body (3) includes a connecting pipe (31) and a plurality of baffles (32). The connecting pipe (31) is rotatably disposed on the other side of the separation shell (2). The driving member (4) is connected to the connecting pipe (31). The connecting pipe (31) forms the channel. One end of the connecting pipe (31) is used to connect to the primary air-powder pipe (300). The other end of the connecting pipe (31) is opposite to the dense phase zone. The other end of the connecting pipe (31) is open. The other end of the connecting pipe (31) is provided with a plurality of connecting holes distributed along its circumference. The baffles (32) are disposed on one side of the connecting pipe (31) in the connecting holes.

3. The pulverized coal gas flow separation and redistribution device (100) according to claim 1, characterized in that, Further including dynamic and static annular seals (5), the dynamic and static annular seals (5) are provided between the rotating body (3) and the separation shell (2) and between the rotating body (3) and the primary air-powder pipe.

4. The pulverized coal gas flow separation and redistribution device (100) according to claim 1, characterized in that, It further includes a partition (6) disposed at the other end of the bend (1), the partition (6) separating the dense phase region and the dilute phase region.

5. The pulverized coal gas flow separation and redistribution device (100) according to claim 4, characterized in that, The bend pipe (1) includes an arc-shaped section (11) and a partition section (12). One end of the arc-shaped section (11) is used to be located at the outlet of the medium-speed coal mill separator (200). The other end of the bend pipe (1) is connected to the partition section (12). The partition section (12) is tangent to the arc-shaped section (11). The separation shell (2) is connected to the partition section (12). The partition plate (6) is provided inside the partition section (12).

6. The pulverized coal gas flow separation and redistribution device (100) according to claim 1, characterized in that, The separation shell (2) includes an annular shell (21) and a conical shell (22). The annular shell (21) is located on the other side of the separation shell (2), and the conical shell (22) is located on one side of the separation shell (2). The conical shell (22) includes a large-diameter end and a small-diameter end. The large-diameter end is connected to the annular shell (21), and the small-diameter end is used to connect to the medium-speed coal mill separator (200).

7. The pulverized coal gas flow separation and redistribution device (100) according to claim 1, characterized in that, It further includes a return powder pipe (7) and an air lock plate (8), one end of the return powder pipe (7) is connected to one side of the separation shell (2), the other end of the return powder pipe (7) is used to connect to the medium-speed coal mill separator (200), and the air lock plate (8) is inside the return powder pipe (7).

8. The pulverized coal gas flow separation and redistribution device (100) according to claim 7, characterized in that, The other end of the return powder pipe (7) is located at the edge of the medium-speed coal mill separator (200), and the other end of the return powder pipe (7) is spaced apart from the outlet of the medium-speed coal mill separator (200).

9. The pulverized coal gas flow separation and redistribution device (100) according to claim 1, characterized in that, The drive unit (4) is a frequency converter drive device.

10. A medium-speed coal mill, characterized in that, include: Separator (200); A pulverized coal airflow separation and redistribution device (100), wherein the pulverized coal airflow separation and redistribution device (100) is as described in any one of claims 1 to 9, one end of the arc-shaped section (11) of the bend (1) is located at the outlet of the separator (200), and one side of the separation shell (2) is connected to the separator (200); and The primary air-powder pipe (300) is connected to the rotating body (3).

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