JP2742669B2 - Variable classification point cyclone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cyclone apparatus for classifying and collecting powder having a particle size distribution, and variably adjusting a classification point of the powder to produce a powder having an arbitrary particle size. The present invention relates to a classifying point variable type cyclone device which selectively collects with high accuracy.

The "powder" used here has a particle diameter of 1 mm.
Hereinafter, a “fine powder” (hereinafter referred to as “fine powder”) of a μm level is considered, and specifically, several μm to one hundred and several tens μm.
Is the target, but this range is not the limit of application. Note that the term “granules” is not used.

[0003]

2. Description of the Related Art In the field of handling fine powder having a particle size of μm level or smaller, not only the selection of materials but also the resolution of technical problems such as higher precision of technology and higher quality of products. It has been found that the magnitude of the surface area of the powder, which affects the physical and chemical properties of the material, that is, the particle size and the particle size distribution of the powder, influence the expected effects, and are regarded as extremely important.

Here, a more sophisticated classification technique is required to adjust the particle size (distribution) of the powder used, and a coarse powder and a fine powder in the powder can be conventionally separated and selectively collected (recovered). Various cyclone devices or cyclone classifiers have been proposed.

[0005] For example, in Japanese Utility Model Laid-Open No. 4-50149, "Cyclone" (hereinafter referred to as a known device), an inverted conical body is provided with an enlarged wall in an inclined posture to re-spray powder (in the specification, powder and granules). The prevention effect is improved. In addition, it is described that a movable cone (a cone in the specification) is housed in the enlarged wall portion and blow-down is combined to enhance the scattering prevention effect.

[0006] Japanese Patent Application Laid-Open No. 4-349949, "Cyclone type dry classification device" (hereinafter, known device).
In the upper part of the cyclone tower, a spiral slide wall is provided in the spirally formed powder introduction part, and the cross-sectional area of the blowing tip of the air flow containing the dispersed powder is variably configured to change the classification point. I'm trying.

In Japanese Unexamined Patent Publication No. Hei 6-238197, "cyclone apparatus" (hereinafter referred to as "known apparatus"), a cone is formed from the lower side to the inside of the cylinder at the opening communicating part with the lower end of the cylinder above the coarse powder collecting means. A movable cone (a block or a conical block for forming a gap in the specification) that moves upward and downward so as to face the apex of the shape and forms an annular gap therebetween is provided to change the classification point. I have.

[0008] It is an object of the present invention to solve the drawbacks that the above-mentioned known apparatus has an enlarged wall in a barrel in the structure of a cyclone tower and that the classification point is fixedly determined by the structure of the above-mentioned known apparatus and the cyclone tower. In this respect, it is worth considering.

In particular, regarding the present invention, when a known apparatus and a known apparatus are positively evaluated, powders having different classification points are classified by one apparatus to cope with changes in manufacturing conditions and quality.
In addition, the point that the applicability to equipment as a dust collecting apparatus is improved can be read as the objective effect.

[0010]

However, when the problems of classifying point movement and classifying performance are emphasized, each of the above-described characteristic configurations in the known apparatus is an individual improvement means, and the following problems are caused. was there.

[0011] The known device has an enlarged wall portion in the barrel (inverted conical body) and has the advantage of preventing re-scattering and enhancing the powder collecting effect. Does not describe the intended effect. For the present invention, the barrel of this structure must be modified.

The known device has a guide plate (sliding wall) which can move forward and backward in the powder introduction portion, but this configuration alone has a disadvantage that the movable range of the classification point is relatively narrow. Also,
It can be said that reducing the guide plate spacing ratio is not practical because the pressure loss in the barrel increases.

Although the known apparatus has a movable cone, the movable range of the classification point is widened by using only this configuration, but there is a disadvantage that the particle size distribution is widened and the classification performance is adversely affected.

[0014] Therefore, there is a need to provide a technical means for absorbing the individual advantages of the above-mentioned known device, removing the disadvantages, and improving the classification performance in classifying point movement as a whole.

[0015] By the way, several μm
As a powder in which particles of up to one hundred and several tens of μm are mixed, there is typically coal ash (fly ash) discharged from a pulverized coal combustion boiler. But there is about 5
It is only about 0%.

One reason for this is that, due to the properties of fly ash (generally, the particle size distribution is wide and the particle size is not uniform, or the range of changing the classification point is narrow, etc.), it is necessary to classify the particle size to an arbitrary particle size. It is in a difficult point.

On the other hand, fly ash is a spherical particle,
It is known to have various characteristic properties physically and chemically. In particular, if fly ash having a small particle size and a narrow particle size distribution width can be classified and collected, it is considered that a more excellent function is produced. Therefore, if the required particle size can be adjusted according to the application such as highly fluidized concrete and high-strength cement, it is expected that effective utilization can be expanded.

[0018] Under these circumstances, the promotion of the recycling of fly ash has been obligated for the electric power companies, and the scope of the technical solution mainly on fly ash classification has become more specific.

The inventors of the present invention have conducted a study on quality improvement (reformation) in order to effectively use a large amount of fly ash discharged from a power plant, and have included components of a novel cyclone tower body. It has been found that a significant improvement can be achieved by satisfying all the structural and functional advantages of the above-mentioned known devices known as the state of the art, and by using the blow-up and blow-down methods together. The invention device was developed. The apparatus of the present invention completed in this way can be widely applied not only to fly ash but also to powder having a particle size distribution.

The present invention has been made in view of such circumstances, and solves the above-mentioned problems, and can change the classification point of powder having a particle size distribution without deteriorating the classification performance. Moreover, it is an object of the present invention to provide a variable classification point type cyclone device capable of collecting powder of an arbitrary particle size, which was conventionally insufficient, by enhancing the effect of preventing the scattering of coarse particles and the effect of retaining the classification performance. It is the purpose.

[0021]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a variable classification point type in which the classification point of powder is variably adjusted to selectively collect powder having an arbitrary particle size. In a cyclone device, a cyclone tower body having a barrel having a straight cylinder portion and an inverted truncated conical portion formed in a downward direction is connected to the inner wall of the cyclone tower body. A circle in which a cross-sectional area of an air flow blowing tip is variably adjusted by forming a reciprocating slide wall inside a full-circular spiral powder introduction means provided in a straight cylindrical portion for suction in a circumferential direction. An arcuate movable guide plate; and a vortex flow formed by a variable length hanging down from the center position of the upper part of the barrel into the straight barrel part and opening at the lower end and the introduced airflow swirling along the inner circumferential wall of the barrel. Up and down movable type for collecting fine powder by applying a weak negative pressure to the center from above Mouth tube; an enlarged portion in which the diameter of the inverted frustoconical portion is increased in the tangential direction of the barrel at the approximate middle position of the barrel to form a stepped structure consisting of two vertical stages with a vertical posture, An enlarged section having an edge formed by forming a canopy of a truncated conical part, and providing a lower end of the upper inverted truncated conical part in a lower part of the inverted truncated conical part with an edge part hanging down in a predetermined length so as to communicate with the opening; Is provided at an opening connection portion of coarse powder collecting means for collecting coarse powder settling by riding on the vortex, so that a cone-shaped apex faces from the lower side toward the inside of the upper barrel. A movable cone body which moves up and down to form an annular gap between them; and an air supply port and an exhaust port provided on the upper wall surface of the coarse powder collecting means accommodating the movable cone body to adjust the vortex velocity from outside. Blow-up and blow-up to augment classification point movement It is characterized in that it has and a down mechanism.

In particular, the characteristic configuration of the barrel is that an enlarged truncated cone-shaped portion is formed in the inverted truncated cone shape portion to form a stepped inverted truncated cone shape having two vertical stages in the vertical posture, The upper inverted truncated cone-shaped portion is provided with an enlarged portion formed by increasing the aperture diameter at the lower end in the tangential direction of the barrel, and is connected to the lower inverted truncated cone shaped portion having the canopy as the upper inverted truncated cone shaped portion. The lower end is provided with an edge portion which is suspended for a predetermined length in the lower inverted truncated conical portion, and communicates with the opening.

Further, a rectifying cylinder for preventing a reduction in the collection efficiency of the fine powder may be incorporated in the vertically movable outlet pipe as the fine powder collecting means.

[0024]

A well-known device such as a stepped inverted frustoconical portion formed by providing an enlarged portion with an edge on the barrel and a movable guide plate (sliding wall) and a movable cone (cone or block) in the powder introduction means. Satisfies all the structural and functional advantages seen in the above, and by adopting a blow-up and blow-down mechanism, the classification point can be changed without deteriorating the classification performance, and the effect of preventing the scattering of coarse particles and The effect of retaining the classification performance is enhanced to enable collection of powder having an arbitrary particle size.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic longitudinal sectional view showing a tower structure of a variable classification point cyclone apparatus (hereinafter referred to as the apparatus of the present invention) and a schematic plan sectional view of a powder introducing means.

Here, 1 is a cyclone tower main body, 2 is a barrel, 21 is a straight cylinder, 22 is an inverted truncated cone, 22a is an upper inverted truncated cone, 22b is a lower inverted truncated cone, and 23 is Enlarged portion with edge, 23a is an enlarged portion, 23b is an edge portion, 3 is a powder introducing means, 31 is a movable guide plate, 4 is a vertically movable outlet pipe (fine powder collecting means), 41 is a rectifying cylinder, 5 is a coarse tube. Powder collecting means, 6 is a movable cone, 7 is an air supply port (blow-up mechanism), 8 is an exhaust port (blow-down mechanism), and X is a classifying point variable cyclone device (the present invention device). In the drawing, h indicates the displacement in the vertical movement of the movable cone. (same as below)

FIG. 2 is a system diagram of a fly ash classification apparatus on a bench scale scale incorporating the apparatus (X) of the present invention. Note that reference numerals and descriptions of related devices and each line are omitted.

As shown in FIG. 1, the characteristic structure of the device (X) of the present invention is that a barrel (2) having a straight cylindrical portion (21) on the upper side and an inverted truncated conical portion (22) on the lower side. Is provided on the straight cylindrical portion (21) for sucking the air flow containing the dispersed powder in the circumferential direction along the inner wall surface of the cyclone tower body (1). A movable guide plate (31) having an arc shape in which a slide wall which can advance and retreat is formed inside the powder-like powder introducing means (3) so as to variably adjust a cross-sectional area of an airflow blowing tip; (2) The vortex flow formed by the air flow introduced from the center position of the upper portion to the straight tube portion (21) to be variably suspended in the variable length and opening at the lower end and swirling along the inner peripheral wall of the barrel (2). A vertically movable outlet pipe (4) for recovering fine powder by applying a weak negative pressure to the center from above; at a roughly intermediate position of the barrel (2) An inverted truncated cone-shaped portion (22) is provided with an enlarged portion (23a) in which the iris diameter is increased in the tangential direction of the barrel (2) to provide a stepped structure having two vertical stages and a lower inverted truncated cone. The canopy of the shape portion (22b) is formed, and the lower end of the upper inverted truncated cone shape (22a) is provided with an edge portion (23b) that is suspended for a certain length in the lower inverted truncated cone shape (22b) so as to communicate with the opening. An enlarged portion with an edge (23) provided at an opening connection portion of coarse powder collecting means (5) for opening and connecting the lower end of the barrel (2) and collecting coarse powder settling on the vortex; A movable cone (6) opposing and moving up and down to form an annular gap between the conical apex so as to face the inside of the upper barrel (2) from the lower side; An air supply port (7) and an exhaust port (8) are provided on the upper wall surface of the coarse powder collecting means (5) containing the body (6). Is intended to and a blow-up and blowdown mechanism to augment adjustments to classification point movable swirl velocity from the section.

The function of each component will be described below.

The following description of the operation and effect of each component of the present invention or the apparatus of the embodiment is based on facts confirmed experimentally, and is not affected by scaling. Experimental results (results, considerations and drawings)
Will also be added to the description. FIG. 3 is a schematic diagram of the configuration of the experimental apparatus.

The enlarged section with edge (23) is provided with an enlarged section (23a) in which the aperture diameter of the inverted truncated cone-shaped section (22) is increased in the tangential direction of the barrel at a substantially intermediate position of the barrel (2). By adopting a stepped structure consisting of two upper and lower postures, coarse particles are prevented from being mixed into the fine powder in the barrel (2), the particle size distribution width is narrowed (improved classification performance), and the cyclone It contributes to reducing pressure loss.

In addition, the enlarged portion (23a) is used as a canopy of the lower inverted truncated cone shape (22b), and the lower end of the upper inverted truncated cone shape (22a) is formed inside the lower inverted truncated cone shape (22b). The above-mentioned function (or effect) can be augmented by providing an edge portion (23b) hanging down for a certain length so as to communicate with the opening.

Experiments have confirmed the effect of the enlarged section with an edge exerting the above-mentioned effects on the classification performance, and FIG. 4 shows a comparison of partial separation efficiency curves for four types of cyclones having different tower structures. VS. Data plot of particle size (partial separation efficiency curve).

As can be seen from the figure, the partial separation efficiency curve (ΔX type dashed line in the figure) in the apparatus configuration of the present invention rises most sharply, and it can be said that the classification performance is improved.

FIG. 5 is a data plot of the weight-based particle size frequency vs. the particle size showing the weight-based particle size frequency distribution in the filter section comparing the configuration of the present invention with the standard type (conventional type) configuration. .

As can be seen from the figure, the weight-based particle size frequency distribution (width) in the configuration of the apparatus of the present invention is narrow, and it can be said that the classification performance is improved. In the figure, the shaded area is the area showing the effect of preventing coarse particle contamination.

The movable guide plate (31) slides in the circumferential direction to change the radial distance between the leading end of the guide plate and the inner wall of the cyclone upper part (changes the cross-sectional area of the leading end of the air flow), thereby changing the leading end of the guide plate. At the inlet.

In this operation, the following interval ratio (g in the attached drawings) is used as an index. If the interval ratio is reduced (increased inlet flow rate), the centrifugal effect becomes stronger, and the particle diameter in the radial direction increases. Since the moving distance is reduced, it contributes to shifting the classification point to the smaller diameter side. Spacing ratio = (width between guide plate tip and cyclone wall [mm] / cyclone inlet width [mm])

The effect on the classification point when moving the guide plate supporting the above-mentioned effects is confirmed by experiments, and FIG. 6 shows the partial separation showing the effect on the 50% separation diameter (classification point) of the movable guide plate. It is a data plot (partial separation efficiency curve) of efficiency vs. particle size.

Movable cone (6) When the effective area of the inlet (opening connection portion) surface of the coarse powder collecting means and the average air flow rising speed are changed by the vertical movement (h in the attached drawing ) of the movable cone, the inside of the cyclone is changed. By increasing or decreasing the average residence time of the particles (in the barrel), it contributes to widening the movable range of the classification point.

Here, the combined effect of using the movable guide plate (31) and the movable cone (6) together has been confirmed by experiments, and FIG. 7 shows a classification point based on the combined effect of the movable guide plate and the movable cone. It is a data plot (partial separation efficiency curve) of partial separation efficiency vs. particle size showing the influence on classification performance at the time of change.

In the figure, the solid lines indicated by circles and triangles indicate the vertical movement of the movable cone (6) without using the movable guide plate (31) (g = 1 in the figure) (h = 10 mm, 8 mm in the figure). ) Alone was used to verify the classification performance when the classification point was changed, and when the movable cone (6) was moved from the 10 mm position to the 8 mm position, 50
The slope of the partial separation efficiency curve at% separation diameter (classification point) is small. Therefore, in this case, as described above, it is understood that the classification performance tends to deteriorate as a disadvantage of the known device.

On the other hand, the broken lines marked with □ and Δ indicate the classification when the classification point is changed by using the movable guide plate (31) and the movable cone (6) together (g = 0.9, h = 10 mm, 8 mm in the figure). The performance was verified. When the distance ratio (g in the figure) of the movable guide plate (31) was set to 0.9 and the movable cone (6) was moved from the 10 mm position to the 8 mm position, a 50% separation diameter (classification point) was obtained. There is almost no difference in the slope of the partial separation efficiency curve in ()). Therefore, in this case, it is understood that the classification performance is maintained (there is a holding effect).

Blow-up mechanism (7) Coarse-powder collecting means (5) Provided with an all-circumferential spiral blow-up inlet (air supply port 7) on the upper wall surface and forced air supply from outside to increase the average air flow rise speed Then, particles other than the coarse particles are pushed up inside the cyclone (inside the barrel), thereby contributing to shifting the classification point to the large diameter side.

The effect of the change in the blow-up flow rate ratio, which supports the above-mentioned effects, on the classification point has been confirmed by experiments. FIG. 7 shows the effect of the blow-up flow rate ratio on the 50% separation diameter (classification point). It is a data plot (partial separation efficiency curve) of partial separation efficiency vs. particle size.

Blow-down mechanism (8) Coarse powder collecting means (5) A blow-down suction port (exhaust port 8) is provided on the upper wall surface to increase the downward velocity component near the cyclone cone wall by forcible suction from the outside. It increases the collection efficiency of coarse powder and contributes to slightly shifting the classification point to the smaller diameter side.

Here, the powder suction-recovered by blowdown has an average particle diameter intermediate between fine powder and coarse powder, and it is possible to collect three different particle diameters at a time, which is significant.

Normally, the movable cone (6) and the following blow-up and blow-down mechanisms are operated in combination.

Vertically movable outlet pipe (4) By changing the height of the outlet pipe of cyclone (1),
It contributes to increasing or decreasing the average residence time of the fine powder and slightly changing the classification point. When the outlet pipe is higher than the reference point, the average particle diameter of the fine powder is small, and when the outlet pipe is low, the average is large. In addition, a rectifying cylinder (41) is incorporated to prevent a reduction in the collection efficiency due to turbulence of the updraft in the outlet pipe.

As described above, the apparatus (X) of the present invention satisfies all the structural and functional advantages described above, and can widely change the classification point without deteriorating the classification performance.
In addition, it is possible to achieve a technical solution to augment the effect of preventing the scattering of coarse particles and the effect of maintaining the classification performance, thereby enabling collection of powder having an arbitrary particle size.

[0052]

The present invention has the above-described structure, and has the following advantageous effects.

(1) It is possible to collect powder having an arbitrary particle size by uniforming the particle size without having a complicated control mechanism and changing the classification point in a wide range. In addition, the effect of preventing the coarse particles from scattering and the effect of maintaining the classification performance can be increased.

(2) By means of a blow-down mechanism, three types of powder having different average particle diameters of fine powder, coarse powder and blow-down powder can be collected by one apparatus.

(3) For a powder having a particle size distribution,
Since the powder can be classified into an arbitrary particle size and collected according to the application, it can contribute to quality improvement (or higher quality). In particular, the use of fly ash can be expanded to cement materials and the like (high value-added use).

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view showing a tower structure of an apparatus of the present invention, which is one embodiment, and a schematic plan sectional view of a powder introducing means.

FIG. 2 is a system diagram of a fly ash classification device on a bench scale scale incorporating the device of the present invention.

FIG. 3 is a schematic configuration diagram of an experimental apparatus.

FIG. 4 is a data plot (partial separation efficiency curve) of partial separation efficiency vs. particle size showing comparison of partial separation efficiency curves in four types of cyclones having different column structures.

FIG. 5 is a data plot of weight-based particle size frequency vs. particle size showing a weight-based particle size frequency distribution in a filter unit comparing the device configuration of the present invention with a standard type (conventional type) configuration.

FIG. 6 is a data plot (partial separation efficiency curve) of partial separation efficiency vs. particle size showing the effect on the 50% separation diameter (classification point) of the movable guide plate.

FIG. 7 is a data plot (partial separation efficiency curve) of partial separation efficiency vs. particle size showing the effect on classification performance when the classification point is changed by the combined effect of the movable guide plate and the movable cone.

FIG. 8: 50% separation diameter of blow-up flow ratio (classification point)
5 is a data plot (partial separation efficiency curve) of partial separation efficiency vs. particle size showing the effect on the particle size.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cyclone tower main body 2 Body 21 Straight cylinder part 22 Inverted truncated cone shape part 22a Upper inverted truncated cone shape part 22b Lower inverted truncated cone shape part 23 Enlarged part with edge 23a Enlarged part 23b Edge part 3 Powder introduction means 31 Mobile guide Plate 4 Up / down movable outlet pipe (fine powder collecting means) 41 Rectifier cylinder 5 Coarse powder collecting means 6 Movable cone 7 Air supply port (blow-up mechanism) 8 Exhaust port (blow-down mechanism) X Classification point variable cyclone device

Claims (4)

(57) [Claims] 1. A cyclone device for classifying and collecting powder having a particle size distribution, wherein the classification point of the powder is variably adjusted to selectively collect powder having an arbitrary particle size. A cyclone tower body having a barrel having a straight cylinder portion and an inverted frustoconical shape portion connected downward, wherein a cyclone tower body is provided. A retractable slide wall is formed inside the full-circular spiral powder introduction means provided in the straight cylindrical portion to suck in the circumferential direction along the inner wall surface of the An arc-shaped movable guide plate which is adjusted; a variable length hanging down from the center position of the upper part of the barrel into the straight part, the lower end of which is opened, and the introduced air flow swirls along the inner circumferential wall of the barrel. Fine powder is collected by applying a weak negative pressure from above to the center of the vortex formed by Up and down movable outlet pipe for adjusting the diameter of the inverted frustoconical portion at the approximate middle position of the barrel, and an enlarged portion with a diameter increased in the tangential direction of the barrel. With the structure, the lower inverted frustoconical shape canopy is formed, and the lower end of the upper inverted frustoconical shape is provided with an edge hanging down a certain length in the lower inverted frustoconical shape to connect the opening. An opening connected to the lower end of the barrel and provided at an open connection of coarse powder collecting means for collecting coarse powder settling on the vortex, and having a conical shape from the lower side toward the upper barrel. A movable cone which moves upward and downward so as to face the apex to form an annular gap therebetween; and an air supply port and an exhaust port are provided on a wall surface above the coarse powder collecting means for accommodating the movable cone. To adjust the vortex velocity from outside to increase the classification point movement Classification point, characterized by comprising a low-up and blowdown mechanism tunable cyclone. 2. The cyclone tower main body has a barrel having an upwardly-directed truncated cone portion and an inverted truncated cone-shaped portion or an inverted truncated cone-shaped portion having an enlarged wall portion connected downward, and is connected to the straight cylinder portion for dispersion. A powder introduction means having a slide wall which can advance and retreat for circumferentially sucking the air flow containing the powder along the inner wall surface of the cyclone tower main body, and a fixed length from the center position of the upper part of the barrel into the straight cylinder part. A fine powder collecting means for collecting a fine powder by applying a weak negative pressure from above to a central portion of a vortex formed by a suspended, lower end opening and an introduced air flow swirling along the inner peripheral wall of the barrel. A coarse powder collecting means for collecting coarse powder that is connected to the lower end of the barrel and is settled on the vortex,
Movable to oppose and move up and down such that a conical apex portion faces from the lower side toward the inside of the upper barrel in the enlarged wall portion or the opening connecting portion at the lower end of the barrel to form an annular gap therebetween. A cyclone device having a conical body, wherein an enlarged truncated cone-shaped portion is formed in the inverted truncated cone-shaped portion of the barrel to form a stepped inverted truncated cone-shaped portion having two vertical stages in a vertical posture, and The upper inverted truncated cone-shaped portion is provided with an enlarged portion formed by increasing the aperture diameter at the lower end in the tangential direction of the barrel, and is connected to the lower inverted truncated cone shaped portion having the canopy as the upper inverted truncated cone shaped portion. A classifying point variable type cyclone device, wherein an edge portion is provided with a lower end hanging down a predetermined length in a lower inverted truncated cone shape and communicating with an opening. 3. A fine powder collecting means is a vertically movable outlet pipe for adjusting the average particle diameter in fine powder collection by increasing or decreasing the average residence time of fine powder so as to be displaceable in the vertical direction, and collecting fine powder. 3. The variable classification point cyclone device according to claim 2, further comprising a rectifying cylinder for preventing a decrease in efficiency. 4. A blow-up and blow-down mechanism for providing an air supply port and an exhaust port on the upper wall surface of the coarse powder collecting means accommodating the movable cone and adjusting the vortex velocity from the outside to increase the classification point movement. Claim 2 equipped with
Classification point variable type cyclone device described.