JP4290922B2 - Cyclone equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cyclone apparatus that classifies fine powder.
[0002]
[Prior art]
Conventionally, this type of cyclone apparatus is widely used because it has a simple structure and can be installed at low cost for classification of powder. In addition, the cyclone device is also used as a coal gasification combined power plant (IGCC) in thermal power generation and a dust collector of an incinerator.
[0003]
FIG. 9 is an explanatory diagram showing a schematic configuration of an example of a conventional cyclone device.
As shown in FIG. 9, the powder to be classified is continuously supplied from the feeder 1 to the lower powder disperser 2 by the feeder screw 1a.
The powder disperser 2 is for dispersing the agglomerated powder in a primary particle state. The powder that has passed through the powder disperser 2 passes through the powder transport pipe 3 and is sucked into the powder introduction part 6 of the cyclone tower body 5 together with air from the air intake port.
[0004]
The cyclone tower main body 5 has an upright cylindrical shape, and includes an upper straight cylindrical portion 5 a and a lower funnel-shaped tapered portion 5 b, and the lower end is open to the coarse powder reservoir 8. Moreover, from the ceiling part of the cyclone tower 5, the exhaust pipe 7 for taking out fine powder hangs down to the position of the fixed height inside a tower main body, and the negative pressure from the blower 10 is given. In addition, 7b is a filter provided in the fine powder conveyance tube 7a for collecting fine powder.
[0005]
The cyclone apparatus is roughly classified into an all-circular spiral inlet type and a tangential inlet type depending on the structure of the powder introduction part. 10 and 11 are perspective views showing the outer shape of the above-mentioned two types of cyclones.
FIG. 10 is a perspective view showing an all-circular spiral inlet type cyclone tower that constitutes the powder introduction portion 6 so that the powder is introduced along the entire circumference of the straight cylinder portion 5a of the cyclone tower. .
FIG. 11 is a perspective view showing a tangential inlet type cyclone tower in which the powder introduction part 60 is configured so as to introduce powder into the inside from the outer tangential direction of the straight cylinder part 50a of the cyclone tower.
Regardless of the type of the cyclone tower 5, in the configuration of FIG. 9, coarse powder settles on the vortex inside the cyclone tower 5, and a weak negative pressure from the primary air take-out cylinder 7 Fine powder is taken out of the slag and classified.
[0006]
However, recently, the cyclone apparatus has a small velocity component in the swirl direction of the flow due to the wall surface near the top wall of the cyclone tower, and centrifugal force is not applied to the particles. It has been found that it tends to flow in the central direction and become difficult to collect.
Therefore, in order to obtain even higher dust collection performance, the yield is improved by utilizing the fact that the powder is concentrated at the lower part of the inlet by the inlet pipe having a lower curvature, giving a large swirl speed. A "centrifugal force dust collector" is proposed in JP-A-6-320055.
[0007]
[Problems to be solved by the invention]
The "centrifugal force dust collector" disclosed in Japanese Patent Laid-Open No. 6-320055 does not provide a sufficient improvement effect especially with respect to the collection efficiency of fine particles, although an improvement effect is seen as compared with the previous one. It has been found.
[0008]
In the process of investigating the cause, in the conventional apparatus including the above apparatus, the secondary flow of air is generated in the cyclone tower, and the turbulence is increased in the vicinity of the cyclone inlet. I found
In particular, in the case of fine particles that are difficult to be subjected to centrifugal force, the turbulence of the flow reduces the number of swirling times of the air flow in the tower. Therefore, in this case, the height of the cyclone tower cannot be used effectively, which causes a reduction in particle collection efficiency.
[0009]
The subject of this invention is providing the cyclone apparatus which aimed at the improvement of dust collection efficiency by improving the conventional cyclone apparatus and suppressing generation | occurrence | production of the local eddy current in the cyclone tower in operation.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the invention of claim 1 is directed to a substantially upright cylindrical cyclone tower body (15) and an air flow containing dispersed powder along the inner surface of the cyclone tower body (15). In order to blow in the horizontal direction, in order to exhaust the air in the cyclone tower body (15) upward, and the powder introduction part (16) provided by extending a part of the cyclone tower body in the outer peripheral tangential direction. An exhaust pipe (17) penetrating the center of a top plate (15c) covering the upper part of the cyclone tower body (15), and an angle around the center of the exhaust pipe (17), Boundary between the exhaust pipe (17) and the top plate (15c) in a region between 90 ° and 270 ° when the boundary between the section (16) and the cyclone tower body (15) is 0 ° The air flow generated locally in the space including the part This is a part that inhibits the reverse flow, and effectively changes the thickness of a part of the exhaust pipe (17) so that the part of the exhaust pipe (17) is placed in the space where the reverse flow is generated. It is a cyclone apparatus including the local eddy current suppression part (11) formed by projecting .
[0011]
According to a second aspect of the present invention, in the cyclone device according to the first aspect, the local eddy current restraining portion (11) is configured such that the amount of overhang of the exhaust pipe (17) is the same as that of the outer peripheral surface of the exhaust pipe (17). It is set to 1/3 or less of the length to the inner surface of the cyclone tower body, and the vertical dimension is 1/5 or less of the length from the top plate (15c) to the lowest position of the exhaust pipe (17). It is a cyclone device characterized by being set to .
[0012]
According to a third aspect of the present invention, in the cyclone device according to the first or second aspect, the local eddy current suppressing portion (11) is configured such that the amount of protrusion of the exhaust pipe (17) is the powder introduction portion (16). ) And the cyclone tower body (15) at 0 °, the largest is set at the position of 180 ° and the smallest at the positions of 90 ° and 270 °. The cyclone device is characterized in that it becomes smaller as the distance from the top plate (15c) increases .
[0013]
According to a fourth aspect of the present invention, in the cyclone device according to the first aspect, the local eddy current suppressing portion (13) is a ring provided along a boundary line between the exhaust pipe and the top plate. It is a cyclone device.
[0014]
According to a fifth aspect of the present invention, in the cyclone device according to the fourth aspect of the present invention, the ring (13) has a radial width in a cross section perpendicular to the ring of the ring from the boundary line of the cyclone tower body (15). It is within 1/3 of the length to the inner surface, and the longitudinal width of the cross section is within 1/5 of the length from the boundary line to the lowest part of the exhaust pipe (17). It is a cyclone device.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
As described above, the present inventors pay attention to the occurrence of local unnecessary eddy currents in the cyclone tower during the operation of classifying the powder in the conventional apparatus, and by suppressing the occurrence thereof, We found that the collection efficiency was improved.
[0016]
FIG. 2 is an explanatory diagram showing the results of examining the flow of air blown into the cyclone tower of a conventional cyclone device.
FIG. 2 is a velocity vector diagram in which the state of the air flow in the tangential inlet type cyclone tower shown in FIG. 11 is analyzed by a Navier-Stokes equation with a computer.
The arrows in the figure are velocity vectors in the vicinity of the inside of the top plate that covers the uppermost part of the cyclone tower body, and each of them indicates the direction and speed of air flow at that point.
[0017]
As shown in FIG. 2, in the vicinity of the ceiling of the cyclone tower, a certain range between the boundary line 17b of the top plate and the exhaust pipe and the center of the air flow passage (inside the boundary line L indicated by a two-dot chain line in the figure) ), There is a flow opposite to the swirling direction of the air flow, which causes a reduction in the collection efficiency of the conventional apparatus.
In the present invention, in order to eliminate this drawback, a local vortex suppression unit for suppressing the reverse flow is provided in the air flow passage in the cyclone tower.
[0018]
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. In the embodiment described below, parts having the same functions as those of the above-described conventional example are denoted by corresponding reference numerals, and overlapping drawings and descriptions are appropriately omitted.
FIG. 1 is an explanatory view (perspective view) showing a characteristic part of an embodiment of a cyclone device (a cyclone tower is a tangential input type) according to the present invention having a configuration according to FIG.
In FIG. 1, the local eddy current suppression unit for suppressing the local eddy current is shown together with the main parts (the upper part of the cyclone tower body, the powder introduction part, the exhaust pipe, etc.) around the local eddy current suppression part. A part of the top plate is cut off.
[0019]
In the case of the embodiment of FIG. 1, the local eddy current suppressing unit 11 smoothly changes the effective thickness of the exhaust pipe 17 (corresponding to the exhaust pipe 7 of FIG. 9) within a predetermined range.
The local eddy current suppressing unit 11 may be supported (or attached) on the exhaust pipe 17 side or on the plate 15c (hereinafter referred to as the top plate) 15c that covers the ceiling of the cyclone tower 15. Further, the top plate itself may be processed and deformed by a method not shown to form a similar form.
[0020]
The powder introduction unit 16 blows air containing dispersed powder (not shown) in the horizontal direction along the inner wall surface of the upper portion 15a of the cyclone tower body 15, and corresponds to the powder introduction unit 6 in FIG. To do.
The exhaust pipe 17 applies negative pressure to the central portion of the tower body 15 from above and applies a negative pressure. The exhaust pipe 17 corresponds to the exhaust pipe 7 of FIG. 9, and its lower portion 17a is opened. Yes.
[0021]
In order to effectively change the thickness of the exhaust pipe 17, the portion where the local eddy current restraining part 11 is arranged has an angle (center) where the attachment position of the powder introduction part 16 (air flow inlet) is relative to the center line of the exhaust pipe 17. Angle) θ is 0 °, and a range of 90 ° ≦ θ ≦ 270 ° is preferable.
[0022]
FIG. 3 is a cross-sectional view showing the arrangement state of the local eddy current suppressing unit 11 cut along BB in FIG.
FIG. 4 is a cross-sectional view showing the arrangement state of the local eddy current suppressing unit 11 cut along A-A in FIG. 3.
The thickness t ₁ at the position where the local eddy current suppressing portion 11 swells most outward (position at the central angle θ = 180 °) is 1/3 or less of the cross-sectional width t ₀ of the air flow passage, The width h ₁ is preferably 1/5 or less of the length h ₀ from the ceiling surface of the air flow passage to the lowermost part of the exhaust pipe.
[0023]
FIG. 5 shows an example in which the local vortex suppression unit 11 is attached to the all-circumferential spiral inlet type cyclone of FIG. 10, and the rotational direction of the air flow including the powder flowing into the cyclone is the same as that shown in FIG. Therefore, the swelling of the local eddy current restraining part 11 is in the range of −90 ° ≦ θ ≦ −270 ° with the central angle θ of the inlet of the powder introduction part 6 being 0 °, and its maximum position is It is at a position of approximately −180 °. In addition, about a shape dimension, it may be substantially equivalent to the case of FIG.
[0024]
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
For example, as a modification of the local eddy current suppressing unit 11, there is one as shown in a perspective view of FIG. 6.
Although the shape of the local eddy current suppression unit 12 shown in FIG. 6A is slightly different from that of the local eddy current suppression unit 11, the range in which the local eddy current suppression unit 12 swells smoothly from the boundary line toward the center of the air flow path is 11 is the same.
[0025]
The local eddy current suppression unit 13 shown in FIG. 6B is ring-shaped and is arranged not to be a part of the boundary line but to surround the entire circumference of the exhaust pipe.
FIG. 7 is a cross-sectional view showing the arrangement state of the local eddy current suppressing unit 13 cut along DD in FIG.
FIG. 8 is a cross-sectional view showing the arrangement state of the local eddy current suppressing unit 13 cut along CC in FIG.
Dimensions of the local vortex prevention units 13, the width t ₂ of the left and right cross-section taken along a plane including the ring center of the center line is less one-third of the cross-sectional width t ₀ of the air flow passage, and the length of the upper and lower (Height) h ₂ is 1/5 or less of the length h ₀ from the ceiling surface of the air flow passage to the lowest part of the exhaust pipe.
[0026]
【Example】
The configuration of the cyclone apparatus of the above embodiment was tested in the same manner as in FIG. 9 by providing a local eddy current suppressing unit in the cyclone tower, and the following results were obtained.
In the cyclone apparatus to be used, the raw material powder supplied by the powder feeder 1 is dispersed by the disperser 2 (dispersion nozzle) and introduced into the cyclone tower body 5 together with the air sucked by the blower 10. The raw material powder is usually agglomerated between individual particles, and the agglomerated particles obtained by agglomeration of fine powder behave like a coarse powder, and thus are easily collected by the cyclone tower body 5. Therefore, the dispersion | distribution device 2 was made to disperse | distribute to the state of each particle | grain, and the collection performance of the fine particle | grain was investigated. The coarse powder is collected in the storage tank 8, and the fine powder that could not be collected by the cyclone is collected by the filter 7b. The collection efficiency was calculated by the ratio of the recovered coarse powder.
[0027]
The size of each part of the used cyclone tower body 5 is as follows.
Diameter of the straight cylinder part 5a of the cyclone: 76mm
Cyclone straight cylinder 5a length: 150.5mm
Diameter of the lower end of the cyclone frustoconical part 5b: 56 mm
Cyclone frustoconical part 5b length: 71.5 mm
Vertical width of cyclone inlet: 40mm
Width of cyclone inlet part; 20mm
Outer diameter of discharge pipe 7: 32 mm
Inner diameter of discharge pipe 7: 30 mm
Length of the discharge pipe 7 in the cyclone tower body: 110 mm
Diameter of coarse powder storage tank 8: 101 mm
Coarse powder storage tank 8 length: 215 mm
[0028]
For the test powder, fly ash with a 50% particle size of 2.5 μm was charged at a supply rate of 0.03 g / s, and the blower 10 was adjusted so that the inlet flow rate from the powder introduction unit was 17.5 m / s. The air volume was adjusted.
Put the resin putty gently along the outside of the discharge pipe 7 in the range of 90 to 270 ° so that the maximum thickness is 5 mm at θ = 180 ° with the central angle θ with respect to the discharge pipe 7 at the entrance being 0 °. Fixed and measured.
[0029]
For comparison, a conventional cyclone without a putty (comparative example) was also tested, and in the cyclone using an exhaust pipe with a putty according to the present embodiment, the collection efficiency was 96.8%, and a cyclone without a putty ( In Comparative Example), it was 93.5%. There was no difference in the pressure loss of the cyclone. As described above, in this example, the collection efficiency was significantly improved as compared with the comparative example.
[0030]
In place of the putty, a ring with an outer diameter of 38 mm and a height of 22 mm was inserted into the exhaust pipe and placed in contact with the ceiling surface. Otherwise, the test was performed under the same apparatus and the same conditions. The efficiency was 95.0% and the pressure loss was the same.
[0031]
【The invention's effect】
As described above in detail, according to the present invention, the boundary line where the top plate inner surface of the cyclone tower body is in contact with the outer surface of the exhaust pipe in order to suppress the local vortex generated when the air flow is blown. By providing the local eddy current restraining part along the line, generation of local eddy currents in the cyclone tower in operation can be effectively suppressed, so that it is possible to improve the dust collection efficiency.
[Brief description of the drawings]
FIG. 1 is an explanatory view (perspective view) showing a main part of an embodiment of a cyclone device according to the present invention.
FIG. 2 is an explanatory diagram showing the flow of air blown into a conventional cyclone tower.
FIG. 3 is an explanatory diagram showing an arrangement of local eddy current suppressing units of the cyclone device according to the embodiment of the present invention.
FIG. 4 is an explanatory diagram showing an arrangement of local eddy current suppressing units of the cyclone device according to the embodiment of the present invention.
FIG. 5 is an explanatory view (perspective view) showing the arrangement of local eddy current restraining portions in the all-circumferential spiral inlet type cyclone tower of the cyclone device according to the embodiment of the present invention.
FIG. 6 is a perspective view showing a modification of the local eddy current suppressing unit of the cyclone device according to the embodiment of the present invention.
FIG. 7 is an explanatory diagram showing an arrangement of a ring-shaped local eddy current suppressing unit of the cyclone device according to the embodiment of the present invention.
FIG. 8 is an explanatory diagram showing an arrangement of a ring-shaped local eddy current suppressing unit of the cyclone device according to the embodiment of the present invention.
FIG. 9 is an explanatory diagram showing a configuration example of a conventional cyclone device.
FIG. 10 is a perspective view showing an outer shape of a full-circular spiral inlet type cyclone.
FIG. 11 is a perspective view showing the outer shape of a tangential inlet type cyclone.
[Explanation of symbols]
5, 15 Cyclone tower body 6, 16 Powder introduction part 7, 17 Exhaust pipe 8, 18 Coarse powder storage tank 11, 12, 13 Local eddy current suppression part

Claims (5)

An almost upright cylindrical cyclone tower body,
In order to blow the air flow containing the dispersed powder in the horizontal direction along the inner surface of the cyclone tower body, a powder introduction part provided by extending a part of the cyclone tower body in the outer peripheral tangential direction;
An exhaust pipe provided for exhausting the air in the cyclone tower body upward and penetrating through the center of the top plate covering the upper part of the cyclone tower body;
When the angle around the center of the exhaust pipe is 0 ° between the powder introduction part and the cyclone tower body, the exhaust pipe and the top plate in a region between 90 ° and 270 ° A part that suppresses the reverse flow of the air flow generated locally in the space including the boundary part of the exhaust pipe, effectively changing the thickness of a part of the exhaust pipe, and A cyclone device including a local eddy current suppressing portion formed by projecting into a space where the reverse flow is generated . The cyclone device according to claim 1,
The local eddy current suppressing unit is configured such that the amount of extension of the exhaust pipe is set to 1/3 or less of the length from the outer peripheral surface of the exhaust pipe to the inner side surface of the cyclone tower body, and the vertical dimension is It should be set to 1/5 or less of the length from the top plate to the bottom of the exhaust pipe
A cyclone device characterized by. In the cyclone device according to claim 1 or 2,
The local eddy current suppression unit is the largest at a position of 180 ° when the boundary between the powder introduction unit and the cyclone tower main body is 0 °, and the 90 ° and the 90 ° A cyclone device characterized in that the cyclone device is set to be the smallest at a position of 270 °, and the amount of overhang in the vertical direction decreases as the distance from the top plate increases . The cyclone device according to claim 1,
The cyclone apparatus according to claim 1, wherein the local eddy current suppressing unit is a ring provided along a boundary line between the exhaust pipe and the top plate . The cyclone device according to claim 4,
The ring has a radial width of a cross section perpendicular to the ring of the ring,
It is within 1/3 of the length from the boundary line to the inner surface of the cyclone tower body, and the vertical width of the cross section is within 1/5 of the length from the boundary line to the lowest part of the exhaust pipe A cyclone device characterized by that.

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