JP2018079424A - Solid fuel pulverizer and operation method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid fuel pulverizer and an operation method thereof which can improve classification performance.SOLUTION: A rotary separator comprises a plurality of blades 31 provided rotatably with respect to a coal feed pipe to classify pulverized coal, a frame body 32 arranged above these blades 31, and a blade guide 33 facing this frame body 32 in a peripheral direction. A gap 39 which communicates with a space 37 after the blades 31 have classified pulverized coal and a space 36 before the blades 31 classify pulverized coal and bypass the blades 31 is formed between the frame body 32 and the blade guide 33. A seal member 40 projecting from either one of the frame body 32 and the blade guide 33 to the gap 39 side is provided, and the seal member 40 forms an inclined plane that inclines in a horizontal direction to the space 37 side after the blades 31 have classified pulverized coal.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a solid fuel pulverization apparatus for pulverizing solid fuel such as coal and an operation method thereof.

  In a coal-fired power generation facility, coal is pulverized by a pulverizer among solid fuels, and the generated pulverized coal is used as fuel. The pulverization device pulverizes the coal supplied on the pulverization table with a pulverization roller to pulverize the coal, generates pulverized coal with a classifier, and burns the pulverized coal with the conveying air supplied from the air supply duct. Transport to equipment.

  Here, the pulverized coal conveyed to the combustion device is preferably pulverized coal having a predetermined particle size or less in consideration of combustion performance and the like. For this reason, only pulverized coal having a predetermined particle size or less is allowed to pass through the pulverizer, and pulverized coal exceeding the predetermined particle size (hereinafter, pulverized coal exceeding the predetermined particle size is referred to as “coarse coal”). A rotary classifier is provided that classifies the pulverized coal conveyed to the combustion device by returning it to the table.

  Such a rotary classifier has a rotating blade, and among the pulverized coal passing into the rotary classifier, the pulverized coal is returned to the pulverizing table by repelling the pulverized coal, thereby classifying the pulverized coal. In the vicinity of the circumferential tip of the rotating blade, there is provided a blade guide that is stationary and fixedly supported to guide the blade, and the blade and the blade guide are in contact with each other between the blade and the blade guide. A gap is formed to prevent this. However, of course, the blade does not reach this gap, and the pulverized coal passing through this gap cannot be classified by the blade. Therefore, if pulverized coal passes through this gap, pulverized coal containing unclassified coarse pulverized coal is transported to the combustion device, which may affect combustion performance (hereinafter referred to as unclassified pulverized coal. The problem that the pulverized coal containing the gas passes through the gap and is conveyed to the combustion device is referred to as “short path”).

  In the roller mill described in Patent Document 1, a seal air supply groove is provided in the upper plate of the roller mill, the seal air is caused to flow out from the seal air supply groove toward the gap, the coarse particles that have entered the gap are pushed back, and a short path is prevented. Yes.

JP-A-8-192066

  However, in the roller mill having a configuration in which the seal air flows out from the seal air supply groove toward the gap, it is necessary to supply the seal air uniformly to the gap in order to sufficiently push back the pulverized coal including the coarse coal flowing into the gap. In addition, there is a possibility that a short pass cannot be easily prevented, for example, a high flow rate of sealing air is required. For this reason, pulverized coal containing short-passed coarse pulverized coal is transported to the combustion apparatus, and the classification performance may not be sufficiently obtained.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the solid fuel grinding | pulverization apparatus which can improve classification performance, and its operating method.

In order to solve the above problems, the solid fuel pulverization apparatus and the operation method thereof according to the present invention employ the following means.
That is, the solid fuel pulverization apparatus according to one aspect of the present invention is a solid fuel pulverization apparatus having a rotary classifier, wherein the rotary classifier is provided so as to be rotatable with respect to the coal supply pipe and is pulverized. A plurality of blades for classifying fuel, a frame body arranged above the blades, and a counter member facing the frame body in the circumferential direction, between the frame body and the counter member, The space after the blade classifies the solid fuel and the space before the blade classifies the solid fuel, and a gap that bypasses the blade is formed, and either the frame body or the opposing member A seal member protruding from the one side toward the gap is provided, and the seal member has an inclined surface inclined with respect to the horizontal direction on the space side after the blade classifies the solid fuel.

In the said structure, the sealing member is provided in the clearance gap formed so that a braid | blade may be bypassed between a frame and an opposing member. For this reason, for example, when coal is used as the solid fuel, the pulverized solid fuel (hereinafter, the pulverized solid fuel is referred to as “coal fine powder”) is air-carryed, and the air-carryed coal fine powder is If it is going to flow into a crevice without going through a blade from the space before classifying coal fine powder, inflow is controlled by a seal member. As a result, the coal fine powder conveyed by the air current is short-circuited from the gap between the frame and the opposing member (that is, from the gap bypassing the blade) to the space after the blade classifies the coal fine powder without using the blade. It is possible to suppress passage and inflow. Therefore, it is possible to improve the classification performance of the solid fuel crusher by suppressing the flow of the coal fine powder not classified by the blade into the downstream space after the blade classifies the coal fine powder.
In addition, for example, when the solid fuel crusher is stopped, the coal fine powder may fall due to gravity and accumulate on the seal member. The coal fine powder deposited on the seal member may spontaneously ignite by the surrounding air for airflow conveyance. In the above configuration, the surface on the side where the blade in the sealing member leads to the space after classifying the solid fuel is formed so as to be inclined with respect to the horizontal direction, so the coal fine powder dropped on the sealing member is It slides down by its own weight along the inclined surface and falls. Thus, coal fine powder is hard to accumulate on a sealing member. Therefore, it is possible to prevent coal fine powder from accumulating in a large amount on the seal member and remaining in the gap.

  In the solid fuel pulverizing apparatus according to one aspect of the present invention, the seal member has a horizontal plane extending in the horizontal direction, a vertical plane intersecting the horizontal plane and extending in the vertical direction, and the inclined plane intersecting the vertical plane. The inclination angle of the inclined surface with respect to the horizontal direction may be larger than the angle of repose of the pulverized solid fuel.

In the said structure, since the inclination-angle of an inclined surface is larger than the repose angle of the pulverized coal fine powder, a solid fuel tends to slide down an inclined surface and a solid fuel does not accumulate easily on an inclined surface. Therefore, it can suppress suitably that the pulverized coal fine powder remains in a large amount in the gap.
The seal member has a horizontal plane extending in the horizontal direction. As a result, the airflow including the fine coal powder that has flowed into the gap and collided with the horizontal plane is difficult to flow into the minute gap because the flow resistance flowing into the narrow minute gap provided in the tip direction of the seal member is large. Thus, it can suppress suitably that the coal fine powder conveyed by airflow flows in into a crevice, and passes. Therefore, the classification performance of the solid fuel crusher can be preferably improved.

  In the solid fuel pulverization apparatus according to one aspect of the present invention, a difference between an inclination angle formed by the horizontal surface and the vertical surface of the seal member and an inclination angle of the inclined surface with respect to a horizontal direction is more than 30 °. It can be large.

  In the above configuration, the difference between the inclination angle formed by the horizontal and vertical surfaces of the seal member and the inclination angle of the inclined surface with respect to the horizontal direction is formed to be larger than 30 °. The repose angle of the solid fuel can be exceeded. Therefore, it is difficult to deposit solid fuel on the inclined surface.

  The solid fuel pulverization apparatus according to an aspect of the present invention may include a seal gas ejection unit that ejects a seal gas from a side communicating with a space downstream of the blade with respect to the seal member.

  In the above configuration, since the sealing gas is ejected from the side communicating with the space on the downstream side of the blade, the coal-carrying coal powder that is about to flow into the gap can be pushed back by the sealing gas. Thereby, it can prevent that the coal fine powder conveyed by airflow flows out into the space of the downstream side of a braid | blade through a clearance gap, and can improve the classification performance of a solid fuel crusher. In addition, since the surface of the convex portion of the seal member that leads to the downstream space of the blade is an inclined surface, the seal gas ejected to the seal member easily flows along the inclined surface. As a result, the flow of the seal gas in the gap becomes smooth, and the coal-carryed coal powder that is about to flow into the gap is preferably pushed back. Thereby, it is possible to prevent the coal fine powder conveyed by the airflow from passing through the gap and short-passing without passing through the blade and flowing out into the space after the coal fine powder is classified. Therefore, it is possible to prevent the unclassified coal fine powder from flowing into the space after the coal fine powder is classified, and improve the classification performance of the solid fuel pulverizer.

  In the solid fuel pulverization apparatus according to one aspect of the present invention, the seal member may be provided on the frame.

  In the above configuration, since the seal member is provided on the frame that rotates about the vertical axis direction, the seal member also rotates together with the frame. Thereby, when coal fine powder accumulates on a sealing member, centrifugal force will act on coal fine powder. The coal fine powder on which the centrifugal force is applied moves toward the tip of the seal member (convex portion), and eventually falls from the tip of the seal member (convex portion). Therefore, it can be set as the structure which coal fine powder cannot accumulate more on a sealing member.

  In the solid fuel pulverization apparatus according to one aspect of the present invention, the seal member may be provided on the facing member.

  In the above configuration, the seal member is provided on the opposing member that is stationary and fixedly supported without rotating. Therefore, the flow of seal air is more orderly than the rotating seal member, and the effect of seal air rectification can be expected.

  Further, in the solid fuel pulverization apparatus according to one aspect of the present invention, the inclined portion includes a first inclined surface and a second inclined surface located above the first inclined surface, and the first inclined surface is provided. The inclination angle of the surface with respect to the horizontal direction may be larger than the inclination angle of the second inclined surface with respect to the horizontal direction.

  In the above configuration, the convex portion has the first inclined surface and the second inclined surface. Thereby, the inclination angle of a 1st inclined surface and a 2nd inclined surface can be set to a desired inclination angle, and an inclined surface can be formed in a desired inclination aspect. Moreover, since the inclination angle of the first inclined surface is larger than the inclination angle of the second inclined surface, the inclination angle of the inclined surface can be increased stepwise from above. Accordingly, since the seal gas can be flowed along the inclined surface more suitably, the seal gas is more uniformly passed, the coal fine powder conveyed by airflow is preferably pushed back, and the coal fine powder conveyed by airflow passes through the gap. Thus, it is possible to prevent the coal fine powder from flowing out into the space after the short pass without passing through the blade. Further, it is possible to more reliably prevent the coal fine powder from being loaded on the convex portion.

  Further, the seal member has a plurality of convex portions each formed with the inclined surface, and is disposed on the side of the plurality of convex portions that leads most to the space after the blade classifies the solid fuel. The inclination angle of the inclined surface with respect to the horizontal direction of the convex portion is more than the inclination angle with respect to the horizontal direction of the inclined surface of the convex portion arranged on the side where the blade communicates with the space before the solid fuel is classified. May be small.

  In the above configuration, the inclination angle of the inclined surface of the convex portion arranged on the side where the blade communicates with the space before classification of the solid fuel, that is, the convex portion arranged farthest from the seal gas supply device is large. It has become. As a result, the convex portion arranged at a position close to the seal gas supply device has a channel resistance with the inner peripheral surface of the opposed blade guide as compared with the convex portion arranged at a position far from the seal gas supply device. As a small shape. Therefore, it can be suppressed that the ejection force of the seal gas is weakened to the convex portion arranged at the position farthest from the seal gas supply device. Therefore, the seal gas can be preferably flowed along the convex portion even at the convex portion arranged at a position farthest from the seal gas supply device.

  In the solid fuel pulverization apparatus according to one aspect of the present invention, at least a surface of the gap facing the seal member may be flat.

  In the above configuration, since the surface facing the seal member is formed flat, the pulverized solid fuel is not deposited on this surface. Therefore, the pulverized solid fuel hardly remains in the gap. Moreover, since the opposing surfaces are formed flat, the opposing surfaces do not hinder the flow of the seal gas. Therefore, the seal gas can be preferably circulated from the gap to the upstream space. In addition, since the opposing surfaces are flat, it is possible to suppress an increase in cost with a simple configuration.

  An operation method of a solid fuel pulverization apparatus according to an aspect of the present invention is the solid fuel pulverization apparatus having a rotary classifier, wherein the rotary classifier is provided rotatably with respect to the coal supply pipe and pulverized. A plurality of blades for classifying the solid fuel, a frame body disposed above the blades, and a counter member facing the frame body in the circumferential direction, and between the frame body and the counter member A space after the blade classifies the solid fuel and a space before the blade classifies the solid fuel, and a gap that bypasses the blade is formed, and either the frame body or the opposing member The operation method of the solid fuel pulverization apparatus, wherein the seal member is provided protruding from one side and provided with a seal member, and the seal member is formed with an inclined surface on the space side after the blade classifies the solid fuel. A step of injecting seal gas from the side of the blade that leads to the space after the blade classifies the solid fuel to suppress the crushed solid fuel from passing through the gap; A step of introducing the solid fuel into the rotary classifier by working air may be provided.

  According to the present invention, the classification performance of the solid fuel crusher can be improved. Further, according to the present invention, it is possible to prevent the pulverized solid fuel from accumulating on the seal member.

It is the longitudinal section showing the schematic structure of the solid fuel crusher concerning the embodiment of the present invention. It is the expanded longitudinal cross-sectional view which shows the II part of FIG. It is the expanded longitudinal cross-sectional view of the sealing member which concerns on 1st Embodiment of this invention. FIG. 4 is an enlarged longitudinal sectional view showing a modification of the seal member in FIG. 3. It is the longitudinal cross-sectional view to which the principal part of the solid fuel grinding | pulverization apparatus which concerns on 2nd Embodiment of this invention was expanded. It is the longitudinal cross-sectional view to which the principal part of the solid fuel grinding | pulverization apparatus which concerns on 3rd Embodiment of this invention was expanded. It is a longitudinal cross-sectional view which shows the modification of FIG.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
In the present embodiment, an example in which coal is used as the solid fuel will be described. As shown in FIG. 1, a vertical mill (solid fuel crusher) 1 according to this embodiment communicates with a cylindrical hollow housing 2 that forms an outer shell of the vertical mill 1 and a lower side surface of the housing 2. An air supply duct 3 that supplies air for conveyance is provided inside the housing 2. Inside the housing 2 are a pulverizing table 4 that is supported by the housing 2 so as to be rotatable about a rotation axis along the vertical vertical direction, and a pulverizing roller 5 that pulverizes coal (solid fuel) on the pulverizing table 4. Is housed.

  The housing 2 has a cylindrical side surface portion 2a that defines the side surface of the housing 2, a ceiling surface portion 2b that defines the upper end in the vertical direction of the housing, and a bottom surface portion 2c that defines the lower end in the vertical direction of the housing. A cylindrical coal supply pipe 7 is provided in the upper center portion of the housing so as to penetrate the ceiling surface portion 2 b of the housing 2. The coal supply pipe 7 supplies coal into the housing 2 from a coal supply device (not shown), and extends in the vertical vertical direction to the center position of the housing 2. Further, a rotary separator (rotary classifier) 8 that rotates around the coal supply pipe 7 in the housing 2 and exists in a direction orthogonal to the longitudinal direction of the coal supply pipe 7 is provided. The rotary separator 8 classifies pulverized coal (hereinafter, the pulverized coal is referred to as “coal fine powder”) into particles having a predetermined particle size or less. On the ceiling surface portion 2 b of the housing 2, there is provided an outlet port 9 for discharging pulverized coal, which is coal fine powder having a predetermined particle size or less classified by the rotary separator 8, to the outside of the housing 2.

  The crushing table 4 includes a rotation support portion 15 that is rotatably supported at the approximate center of the bottom surface portion 2 c of the housing 2, and a substantially circular plate-like table portion 16 that is fixed to the upper end of the rotation support portion 15. The rotation support unit 15 is rotationally driven by a driving device (not shown). The table portion 16 is disposed so as to face the lower end portion on the vertical lower side of the coal supply pipe 7 and rotates together with the rotation support portion 15. Further, the upper surface of the pulverizing table 4 extends in the horizontal direction, and has an inclined shape in which the central portion has a height that is higher in the vertical direction than the outer side, and the height decreases from the central portion toward the outer side. The outer periphery is curved upward again. The outer end portion of the table portion 16 and the inner surface of the side surface portion 2 a of the housing 2 are not in contact with each other, and a gap is provided between the table portion 16 and the side surface portion of the housing 2.

  The crushing roller 5 is disposed vertically above the outer peripheral portion of the table unit 16 so as to face the table unit 16. The crushing roller 5 is fixed to the housing 2 via a first support shaft 17, a support arm 18 and a second support shaft 19. The first support shaft 17 extends so as to incline vertically downward from the side surface portion 2a of the housing 2 toward the center portion, and the crushing roller 5 is rotatably supported at the tip portion via a bearing (not shown). Yes. In other words, the crushing roller 5 is rotatably supported in a state in which the crushing roller 5 is inclined vertically above the crushing table 4 so that the upper side faces the center side of the housing 2 rather than the lower side.

  The support arm 18 is supported on the side surface portion 2a of the housing 2 so as to be swingable in the vertical and vertical directions by a second support shaft 19 having an intermediate portion along the horizontal direction. The support arm 18 supports the proximal end portion of the first support shaft 17 on which the crushing roller 5 is rotatably mounted at the distal end portion. That is, the crushing roller 5 is supported so as to be detachable from the upper surface of the crushing table 4 by the support arm 18 swinging in the vertical vertical direction with the second support shaft 19 as a fulcrum. When the pulverizing table 4 rotates in a state where the outer peripheral surface is in contact with the upper surface of the pulverizing table, the pulverizing roller 5 can be rotated by receiving rotational force from the pulverizing table 4.

  A pressing device 20 is provided at the upper end portion on the vertical upper side of the support arm 18, and a stopper 21 is provided at the lower end portion of the support arm 18. The pressing device 20 is fixed to the housing 2 and applies a load that the crushing roller 5 presses against the crushing table 4 via the support arm 18 and the like so as to press the crushing roller 5 against the crushing table 4. The stopper 21 is fixed to the housing 2, restricts the amount by which the crushing roller 5 can rotate vertically downward, and restricts the applied load that the crushing roller 5 presses against the crushing table 4. The stopper 21 is for securing a predetermined gap between the crushing roller 5 and the crushing table 4 when there is no coal on the crushing table 4. This is to prevent the crushing table 4 and the crushing roller 5 from coming into contact with each other (metal touch) even when rotated, and not to be damaged.

  The air supply duct 3 has a rectangular tube shape or a circular tube shape with a substantially rectangular cross section. A duct outlet 25 that opens into the housing 2 is provided at one end of the air supply duct 3, and a duct inlet 26 that opens out of the housing 2 is provided at the other end. The air supply duct 3 is provided so as to extend substantially parallel to the horizontal plane or at a vertically lower side with an inclination angle, and communicates with the side surface portion 2 a of the housing 2. The air supply duct 3 supplies the transfer air into the housing 2 by pushing in the transfer air supplied from an air supply device (not shown) from the duct inlet 26 and discharging it from the duct outlet 25. The conveying air supplied from the air supply duct is blown out from the gap between the pulverizing table 4 and the side surface 2a of the housing 2, and the coal fine powder pulverized by the pulverizing table 4 is conveyed to the rotary separator 8 by airflow.

  Next, the structure of the rotary separator 8 is demonstrated based on FIG.1 and FIG.2. FIG. 2 is an enlarged vertical sectional view of a portion indicated by a two-dot chain line circle II in FIG. The rotary separator 8 extends in the vertical direction (vertical direction) and is rotatably supported by a rotary support body (not shown) provided so as to surround the coal supply pipe 7. And an annular blade guide (opposing member) 33 provided to face an outer end of a blade 31 described later and an outer peripheral surface of a frame 32 described later.

  As shown in FIG. 2, the rotary separator main body 29 includes a disk-shaped upper support 30 having an opening (not shown) at the center and a lower surface of the upper support 30 at a predetermined interval in the circumferential direction. A plurality of blades 31 arranged and fixed, and an annular frame 32 provided along the outer periphery of the upper support 30 and standing from the upper surface of the upper support 30 are provided. The blade guide 33 has a cylindrical inner peripheral surface facing the blade 31, and is provided so as to extend vertically downward from the lower surface of the ceiling surface portion 2 b of the housing 2.

  Each blade 31 is formed in a flat plate shape, is provided along the vertical direction (vertical direction), and is at a predetermined angle with respect to a direction radial to the outer peripheral direction with respect to the center of rotation of the rotary separator 8. It is provided to become. Further, the outer end portion of each blade 31 on the outer peripheral side with respect to the center of rotation of the rotary separator 8 is inclined such that the lower end is closer to the rotation center side of the rotary separator 8 than the upper end.

  Among the fine coal powder that is rotated by the air for transportation, the blade 31 that rotates together with the rotary separator main body 29 is a large fine coal powder that exceeds a predetermined particle size (hereinafter referred to as a large fine coal powder that exceeds a predetermined particle size. The term “coarse coal” is referred to as “coarse coal”, and the air coal transported coarse coal impinges on the blade 31 and obstructs the air transport of the coal. The hindered coarse pulverized coal falls by gravity and is returned to the pulverizing table 4 again to be pulverized again. On the other hand, coal fine powder having a particle diameter smaller than a predetermined particle diameter (hereinafter, coal fine powder having a particle diameter smaller than a predetermined particle diameter is referred to as “pulverized coal”) passes between the blade 31 and the blade 31 on the flow of air for conveyance. Then, it is carried out from the outlet port 9 to the outside of the housing 2. Thus, in the rotary separator 8, the fine coal powder is classified into coarse coal and fine coal by the rotating blade 31. That is, in the housing 2, the upstream space before the coal fine powder before classification (that is, the state in which pulverized coal and coarse coal are mixed) is conveyed and circulated by the blade 31 is classified. (Hereinafter referred to as “upstream space”) 36 and the downstream space after the classified coal fine powder (that is, the state of only pulverized coal) is air-flowed and distributed by the blade 31 that classifies the coal fine powder ( Hereinafter, it is referred to as “downstream space”) 37. The “upstream side” and the “downstream side” referred to here represent “upstream side” and “downstream side” with respect to the blade 31 in the main flow of the conveying air that is the air flow in the housing 2. Yes.

An annular gap 39 is formed between the outer end of the blade 31 and the outer peripheral surface of the frame 32 on the outer peripheral side with respect to the center of rotation of the rotary separator 8, and the inner peripheral surface of the blade guide 33 facing these. It is formed. The gap 39 communicates with the upstream space 36 and the downstream space 37. That is, the gap 39 communicates the upstream space 36 and the downstream space 37 so as to bypass the flow of airflow into the blade 31.
The gap 39 is provided with an annular seal member 40 fixed to the outer surface on the outer peripheral side of the frame body 32. 2 and 3, the seal member 40 is fixed to the outer surface of the frame body 32 and protrudes from the outer surface by a predetermined distance in the direction of the blade guide 33 (peripheral direction). Furthermore, it has the convex part 43 which protrudes in the direction of the blade guide 33, and is arrange | positioned along the up-down direction by multiple (three in this embodiment), and the recessed part 42 formed between the adjacent convex parts 43. In the present embodiment, three convex portions 43 and two concave portions 42 are formed, but this number is not limited, and at least two convex portions 43 and at least one concave portion 42 are formed. In the present embodiment, at least the surface of the inner peripheral surface of the blade guide 33 that faces the seal member 40 is formed to be a flat surface that does not have protrusions that fit into the convex portions 43 and the concave portions 42. . For this reason, the processing of the inner peripheral surface of the blade guide 33 is the same as before, and the cost increase is suppressed.

In FIG. 3, the outer peripheral side is the right side of the drawing with respect to the center of rotation of the rotary separator 8, and the outer peripheral side is the outer side. As shown in FIG. 3, each convex portion 43 includes an upper horizontal plane 43a extending from the fixed portion 41 in the outer circumferential direction, an inclined surface 43b extending outward from the outer end of the upper horizontal plane 43a, and an outer surface of the inclined surface 43b. It has a vertical surface 43c extending vertically downward from the end, and a sewage horizontal surface (horizontal surface) 43d extending horizontally in the inner circumferential direction from the lower end of the vertical surface 43c. The inner end of the sewage plane 43d is connected to the fixed portion 41. In the present embodiment, the relationship between the inclination angle θ1 formed by the sewage horizontal surface 43d and the vertical surface 43c and the inclination angle θ2 formed by the inclined surface 43b and the horizontal surface L1 is as follows.
Inclination angle θ1−Inclination angle θ2 ≧ 30 ° (1-1)
Inclination angle θ2 ≥ angle of repose of fine coal powder (1-2)
It is.
That is, the upper surface of the convex portion 43 is inclined so that the width (thickness) in the vertical direction increases from the tip portion toward the fixed portion by a predetermined distance from the tip portion on the outer peripheral side. In addition, the angle of repose of the coal fine powder is obtained by measurement, for example, in a range of 25 ° to 50 °, and in the vertical mill 1 of the present embodiment, for example, 30 °. The inclination angle θ2 of the present embodiment is an angle larger than the angle of repose of the coal fine powder. For example, θ2 is 30 ° to 60 °. The inclination angle θ1 is set to 90 ° for ease of processing. The tip portion of the convex portion, that is, the vertical surface 43c is close to the inner peripheral surface of the opposing blade guide 33 and is so small that it does not break due to contact with each mechanical error or thermal expansion difference when the rotary separator 8 rotates. There is a gap.
Moreover, Formula (1-1) expresses the relationship which judges simply when the angle of repose of coal fine powder is considered using the numerical value of 30 degrees. That is, the difference between the inclination angle θ1 and the inclination angle θ2 exceeds 30 ° when the inclination angle θ2 becomes smaller, the second inclined surface 52b of the convex portion 43 is leveled, and the inclination angle θ2 is reduced to the fine coal powder. The angle of repose is smaller than that. Further, when the inclination angle θ1 of the convex portion 43 greatly exceeds 90 °, the outer peripheral side tip of the convex portion 43 constituted by the first inclined surface 52c and the second inclined surface 52b may be sharpened with an acute angle. The time for the airflow to pass through the minute gap between the inner peripheral surfaces of the opposing blade guides 33 is shortened, and it becomes difficult to obtain the effect of pushing back the coal dust that has been conveyed by the airflow trying to pass through the minute gap. .

Further, a seal gas ejection part 46 that ejects the seal gas 45 to the seal member 40 may be provided on the ceiling surface part 2 b vertically above the gap 39. The seal gas ejection part 46 ejects the seal gas 45 supplied from a seal gas supply device (not shown) from the seal gas ejection hole 47 into the housing 2. In the present embodiment, a plurality of seal gas ejection portions 46 such as 2 to 8 are provided on the ceiling surface portion 2b so that the seal gas is supplied to the gaps 39 as uniformly as possible. The seal gas ejection hole 47 has an outer end provided in the vicinity of the upper end portion of the blade guide 33 and a seal gas guide portion 48 extending in the vertical direction in the vicinity of the inner end, so that the seal gas is ejected from the seal gas ejection hole 47. The gas is supplied uniformly by the tip portion of the convex portion 43 of the seal member 40. Since the minute gap between the vertical surface 43c at the tip of the convex portion and the inner peripheral surface of the opposing blade guide 33 is narrow, the flow rate of the seal gas 45 passing through this minute gap is increased, and the coal fine powder conveyed by the air current is increased. The effect of pushing back can be easily obtained. That is, since it is easy to obtain the flow rate required for sealing, the supply flow rate of the sealing gas can be reduced.
The seal gas 45 may be, for example, air but an inert gas such as nitrogen gas or carbon dioxide gas when there is concern about the ignition of coal powder.

Next, the main flow of coal supplied from the coal supply pipe 7 onto the pulverizing table 4 will be described with reference to FIGS. 1 and 2.
When coal is supplied from the coal supply pipe 7 into the housing 2 as indicated by an arrow A1 in FIG. 1, the coal is supplied to the central portion on the crushing table 4. At this time, since the crushing table 4 rotates at a predetermined speed, the coal supplied to the central portion on the crushing table 4 moves so as to be dispersed on the outer periphery by centrifugal force, and the whole surface of the crushing table 4 is moved. A certain coal layer is formed at the same time. Thereafter, the coal enters between the grinding roller 5 and the grinding table 4.

  When coal enters between the grinding roller 5 and the grinding table 4, the rotational force of the grinding table 4 is transmitted to the grinding roller 5 through the coal, and the grinding roller 5 rotates as the grinding table 4 rotates. At this time, although the crushing roller 5 tries to rise by coal, the raising operation is suppressed by the pressing device 20 and a pressing load is applied to the coal. Therefore, the crushing roller 5 presses and crushes the coal on the crushing table 4.

  The coal pulverized by the pulverizing roller 5 becomes fine coal powder, and the carrier air (see arrow A2 in FIG. 1) sent from the air supply duct 3 into the housing 2 is blown up from the outer periphery of the pulverizing table 4 while being dried. Ascended by air flow (see arrow A3 in FIG. 1). Foreign matter such as gravel or metal pieces mixed in coal, and coal dust that is so large that it does not rise due to air for conveyance, etc., is separated from the outer peripheral portion of the crushing table 4 by the centrifugal force to the bottom surface portion 2c of the housing 2. Fall into. Below the crushing table 4, a sweeping device (not shown) is provided, and foreign matter and coal fine powder dropped on the bottom surface portion 2 c are discharged to the outside of the housing 2 by the sweeping device.

  The fine coal powder that has been raised by the air for conveyance and conveyed in the airflow flows into the rotary separator 8 and is classified by the rotating blade 31 of the rotary separator 8. It is returned and reground. On the other hand, the pulverized coal passes through the rotary separator 8, is air-flowed by the air for conveyance, and is discharged from the outlet port 9 (see arrow A4 in FIG. 1). Such a flow becomes the main flow of the flow of coal fines. On the other hand, a part of the coal fine powder that has risen by airflow conveyance by the conveying air is not flowed into the rotary separator 8 but is shown by the arrow A5 in FIG. 2 on the outer end of the blade 31 and the outer periphery of the frame 32. Some of them flow into the gap 39 between the surface and the inner peripheral surface of the blade guide 33 and try to pass the inflow to the blade 31 through a short path. The air-carrying coal fines that are about to flow into the gap 39 are suppressed from passing by the seal member 40. Still further, the coal dust (see arrow A5 in FIG. 3) that has been air-flowed to pass between the tip of the convex portion 43 of the seal member 40 and the blade guide 33 is sealed gas ejected from the seal gas ejection portion 46. Pushed back by 45. The coal fines blocked by the seal member 40 and the coal fines pushed back by the seal gas 45 merge with the main flow of the coal fines conveyed by airflow, flow into the rotary separator 8 and are classified, and the pulverized coal flows into the airflow. It is conveyed and discharged from the outlet port 9.

According to this embodiment, there exist the following effects.
In this embodiment, since the sealing member 40 is provided in the gap 39 formed so as to bypass the inflow to the blade 31 between the frame body 32 and the blade guide 33, the coal fine powder conveyed by airflow However, if it is going to flow into the clearance 39 from the upstream space 36, the inflow is suppressed by the seal member 40. As a result, the coal fine powder conveyed by the airflow flows out from the gap 39 between the frame body 32 and the blade guide 33 (that is, from the gap 39 bypassing the inflow to the blade 31) to the downstream space 37. Can be suppressed. Accordingly, it is possible to improve the classification performance of the vertical mill 1 by suppressing the coal fine powder containing coarse pulverized coal from flowing into the downstream space 37 without being classified by the blade 31.
Moreover, since the sewage horizontal surface 43d of the convex portion 43 is substantially parallel to the horizontal surface, the airflow containing the coal fine powder after the airborne coal dust collides with the sewage flat surface 43d is directed toward the tip of the convex portion 43. It is difficult to flow into the narrow gap provided. In this way, the fine coal powder flowing into the gap 39 can be suitably stopped. Therefore, the classification performance of the vertical mill 1 can be preferably improved. Further, the seal member 40 is provided on the frame body 32 which is stationary and fixedly supported without rotating. Therefore, replacement and maintenance of the seal member 40 can be easily performed.
Further, for example, when the vertical mill 1 is stopped, the coal fine powder that has been conveyed by the airflow may drop due to gravity and accumulate on the seal member 40. The coal fine powder deposited on the seal member 40 may spontaneously ignite when the amount becomes large. In this embodiment, since the surface (namely, inclined surface 43b) of the convex part 43 that leads to the downstream space 37 is formed so as to be inclined and fall with respect to the horizontal plane L1, the coal fine powder is a sealing member. 40 is difficult to deposit. Therefore, it is possible to prevent coal fine powder from accumulating in a large amount on the seal member 40 and remaining in the gap 39.

  Moreover, in this embodiment, since inclination-angle (theta) 2 of the inclined surface 43b is larger than the repose angle of coal fine powder, the coal fine powder on the inclined surface 43b is easy to slip down, and it is hard to deposit coal fine powder on the inclined surface 43b. Therefore, it is possible to suitably suppress a large amount of coal fine powder remaining in the gap 39.

  Further, in the present embodiment, since the seal gas 45 is ejected from the downstream space 37 side, the coal fine powder that has been air-flowed to flow into the gap 39 is pushed back by the seal gas 45, and the coal fine powder that has been air-flow conveyed. Can be prevented from flowing into the downstream space 37 through the gap 39, and the classification performance of the vertical mill 1 can be improved. Moreover, since the upper surface of the convex part 43 is the inclined surface 43b, the seal gas 45 ejected with respect to the sealing member 40 tends to flow to the upstream space 36 along the inclined surface 43b. Further, since the minute gap between the vertical surface 43c at the tip of the convex portion and the inner peripheral surface of the opposed blade guide 33 is narrow, the coal gas finely conveyed by the airflow is supplied even if the overall flow rate of the seal gas 45 is small. Since it is easy to obtain a flow velocity for obtaining the effect of pushing back, the seal gas flow rate can be reduced. As a result, the flow of the seal gas 45 in the gap 39 becomes smooth, and the coal dust that has been carried by the airflow to flow into the gap 39 is preferably pushed back, and the coal dust flows out to the downstream space 37 through the gap 39. Can be suppressed. Accordingly, it is possible to improve the classification accuracy of the vertical mill 1 by suppressing the unclassified coal fine powder from flowing into the downstream space 37.

  In this embodiment, since the seal member 40 is provided on the frame body 32 that rotates about the vertical axis direction, the seal member 40 also rotates together with the frame body 32. Therefore, when coal fine powder accumulates on the seal member 40, centrifugal force acts on the coal fine powder. The coal fine powder on which the centrifugal force is applied moves toward the tip of the convex portion 43 and eventually falls from the tip of the convex portion 43. Therefore, it can be set as the structure where coal fine powder is hard to accumulate on the sealing member 40 more.

  Moreover, in this embodiment, since the wall surface (inner peripheral surface of the blade guide 33) in which the sealing member 40 is not provided is formed flat, coal fine powder does not accumulate on this wall surface. Therefore, a configuration in which a large amount of fine coal powder does not remain in the gap 39 can be achieved. Further, since the wall surface is formed flat, the wall surface does not hinder the flow of the seal gas 45. Therefore, the seal gas 45 can be preferably circulated from the gap 39 to the upstream space 36. Further, since the wall surface is flat, a simple configuration can suppress an increase in cost.

[First Modification of First Embodiment]
Next, a modified example of the convex portion of the present embodiment will be described.
The inclined surface of the convex part of this modification has the 1st inclined surface 52c and the 2nd inclined surface 52b, as shown with the broken line of FIG. In the present modification, the lower end of the second inclined surface 52b and the upper end of the first inclined surface 52c are connected. In addition, the inclination angle θ1 ′ formed by the first inclined surface 52c and the sewage plane 43d is formed larger than the inclination angle θ2 ′ of the second inclined surface 52b with respect to the horizontal direction.

According to this modification, the following operational effects can be obtained.
In this modification, since the convex part 43 has the first inclined surface 52c and the second inclined surface 52b, the inclination angles θ1 ′ and θ2 ′ of the first inclined surface 52c and the second inclined surface 52b are set as desired. By setting the inclination angle, the inclined surface can be formed in a desired inclination mode. Further, since the inclination angle θ1 ′ of the first inclined surface 52c is larger than the inclination angle θ2 ′ of the second inclined surface 52b, the inclination angle of the inclined surface formed on the upper surface of the convex portion 43 is decreased from the upper side to the lower side. It can be increased in steps. Therefore, when the seal gas 45 is ejected from the downstream space 37 side and allowed to pass to the upstream space 36, the seal gas 45 can be flowed more uniformly in the circumferential direction along the inclined surface. The effect of pushing back the conveyed coal fines with the seal gas 45 is improved. Moreover, it can prevent more reliably that coal fine powder accumulates on a convex part. Note that the inclination angle θ1 ′ formed by the first inclined surface 52c and the sewage plane 43d is in addition to the preferable angle of the inclination angle θ1 and the inclination angle θ2 described above, and the condition of the inclination angle θ1 ′ is added.
Inclination angle θ1′−Inclination angle θ2 ′ ≧ 30 ° (... (1-1 ′)
Inclination angle θ2 ′ ≧ Repose angle of fine coal powder (1-2 ′)
60 ° ≦ inclination angle θ1 ′ ≦ 90 ° (2-1)
Inclination angle θ1 ′ ≧ Inclination angle θ2 ′ (2-2)
The range of is preferable.
By setting θ1 ′ to 90 ° or less, the seal gas 45 can easily flow into the upstream space 36, and by setting θ1 ′ to 60 ° or more, the edge portion of the convex portion 43 (first inclined surface). The strength of the connecting portion between 52c and the sewage plane 43d) can be ensured.

[Modification 2 of the first embodiment]
Next, a modified example of the seal member of this embodiment will be described.
In this modification, as shown in FIG. 4, the inclination angles of the inclined surfaces 53b, 54b, and 55b of the convex portions 53, 54, and 55 with respect to the horizontal direction are different. The seal member of this modification is positioned below the first convex part 53 positioned below the first convex part 53, the second convex part 54 positioned below the first convex part 53, and below the second convex part 54. And a third convex portion 55. The first convex portion 53 has a first convex portion inclined surface 53b, the second convex portion 54 has a second convex portion inclined surface 54b, and the third convex portion 55 has a third convex portion inclined surface 55b. ing. Θ3 which is an inclination angle of the first convex inclined surface 53b with respect to the horizontal plane L1, θ4 which is an inclination angle of the second convex inclined surface 54b with respect to the horizontal plane L1, and an inclination angle of the third convex inclined plane 55b with respect to the horizontal plane L1. With certain θ5, in addition to the preferable angle of the above-mentioned inclination angle θ1, the condition of the correlation of the current inclination angles θ3, θ4, θ5 is added,
Inclination angle θ1−Inclination angle (θ3, θ4, θ5) ≧ 30 ° (1-1 ”)
Inclination angle (θ3, θ4, θ5) ≥ angle of repose of fine coal powder ... (1-2 ")
60 ° ≦ Inclination angle θ1 ≦ 90 ° (2 ')
Inclination angle θ3 ≦ Inclination angle θ4 ≦ Inclination angle θ5 (3-1)
It is set to be a relationship.

According to this modification, the following operational effects can be obtained.
In this modification, the third convex portion 55 arranged on the lowermost side in the vertical direction, that is, the inclination of the third convex portion inclined surface 55b of the third convex portion 55 arranged at the farthest position from the seal gas ejection portion 46. The angle is getting bigger. Therefore, the convex portion 53 disposed on the upper side that is close to the supply of the seal gas 45 is opposed to the convex portion 55 disposed on the lower side that is far from the supply of the seal gas 45. Since the flow resistance with the inner peripheral surface of 33 is reduced, the ejection force of the seal gas 45 is suppressed from weakening to the third convex portion 55, and the seal gas 45 is suitably also in the third convex portion 55. Can flow along the convex portion.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
This embodiment differs from the first embodiment described above in the position at which the seal member 60 is fixed. About another point, the same code | symbol is attached | subjected similarly to 1st Embodiment, and the description is abbreviate | omitted.
In the present embodiment, the seal member 60 is provided on the inner peripheral surface of the blade guide 33. That is, the fixing portion 41 of the seal member 60 is fixed to the inner peripheral surface of the blade guide 33, the convex portion 43 protrudes toward the frame body 32, and the tip portion of the convex portion 43 is close to the outer surface of the frame body 32.

  In this embodiment, since the seal member 60 is provided on the blade guide 33 that is stationary and fixed, the replacement and maintenance of the seal member 60 can be easily performed.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG.
This embodiment differs from the first embodiment described above in the position where the seal member 61 is provided. About another point, the same code | symbol is attached | subjected similarly to 1st Embodiment, and the description is abbreviate | omitted.

  In the present embodiment, a first guide member 62 that extends downward from the lower surface of the ceiling surface portion 2 b is provided inside the frame body 32. The seal member 61 is disposed in a gap formed between the outer surface of the first guide member 62 and the inner surface of the frame body 32. The seal member 61 is fixed to the outer surface of the first guide member 62. The seal member 61 may be disposed in the gap 65 and may be fixed to the inner surface of the frame body 32. Further, a seal gas ejection portion (not shown in FIG. 6) may be provided on the ceiling surface portion 2b between the first guide member 62 and the outlet port 9. In this case, the seal gas ejected from the seal gas ejection portion flows along the second guide member 63 into a gap 65 formed between the outer surface of the first guide member 62 and the inner surface of the frame body 32.

  Note that the present invention is not limited to the invention according to each of the above embodiments, and can be appropriately modified without departing from the gist thereof. For example, in each of the above embodiments, the case where the surface on the side where the seal member of the gap is not fixed is flat is described. However, the surface on the side where the seal member is not fixed is flat as shown in FIG. Alternatively, the protrusion 64 may be formed. Protrusions or the like that fit into the convex portions 43 and the concave portions 42 are formed so that the coal pulverized coal transported by the air current is less likely to pass through, and even if there is no seal gas 45, a short path can be prevented. However, it is necessary to process the inner peripheral surface of the blade guide 33, and it may be necessary to improve the mutual positional accuracy of the projections 43 and the like that fit into the recesses 42. It becomes possible to cope.

  Moreover, although each said embodiment demonstrated the example in which the inclined surface was formed in linear form, the inclined surface may be formed in curved surface form. In each of the above-described embodiments, the example in which the seal member and the member to which the seal member is fixed is separate is described. However, the seal member may be provided integrally with a member that forms a gap.

  In each embodiment described above, coal is pulverized as a solid fuel. However, other solid fuels such as high-grade coal, low-grade coal, and petroleum coke may be used. The biomass used may be, for example, thinned wood, waste wood, driftwood, grass, waste, sludge, tires, etc. and recycled fuel (pellets and chips) made from these can be crushed. is there.

1 Vertical mill (solid fuel crusher)
2 Housing 3 Air supply duct 4 Crushing table 5 Crushing roller 7 Coal supply pipe 8 Rotary separator (rotary classifier)
9 Exit port 29 Rotary separator main body 31 Blade 32 Frame 33 Blade guide (opposing member)
36 upstream space 37 downstream space 39 gap 40 seal member 43 convex portion 43b inclined surface 45 seal gas 46 seal gas ejection portion 52b second inclined surface 52c first inclined surface 53 first convex portion 53b first convex portion inclined surface 54 Second convex portion 54b Second convex portion inclined surface 55 Third convex portion 55b Third convex portion inclined surface

Claims (10)

In a solid fuel pulverizer having a rotary classifier,
The rotary classifier includes a plurality of blades that are provided so as to be rotatable with respect to the coal supply pipe and classify the pulverized solid fuel, a frame body disposed above the plurality of blades, and the frame body. An opposing member facing in the circumferential direction,
Between the frame and the opposing member, there is a gap that bypasses the blade while communicating the space after the blade classifies the solid fuel and the space before the blade classifies the solid fuel. Formed,
A seal member that protrudes from either one of the frame and the opposing member toward the gap is provided;
The sealing member is a solid fuel pulverizing apparatus in which an inclined surface inclined with respect to a horizontal direction is formed on a space side after the blade classifies the solid fuel. The seal member has a horizontal plane extending in the horizontal direction, a vertical plane intersecting the horizontal plane and extending in the vertical direction, and the inclined plane intersecting the vertical plane,
The solid fuel pulverization apparatus according to claim 1, wherein an inclination angle of the inclined surface with respect to a horizontal direction is larger than an angle of repose of the pulverized solid fuel.   The solid fuel pulverization apparatus according to claim 2, wherein a difference between an inclination angle formed by the horizontal surface and the vertical surface of the seal member and an inclination angle of the inclined surface with respect to a horizontal direction is larger than 30 °.   The solid fuel pulverization according to any one of claims 1 to 3, further comprising: a seal gas ejection portion that ejects a seal gas from a space side after the blade classifies the solid fuel with respect to the seal member. apparatus.   The solid fuel pulverization apparatus according to claim 1, wherein the seal member is provided on the frame.   The solid fuel pulverization apparatus according to claim 1, wherein the seal member is provided on the facing member. The inclined surface has a first inclined surface and a second inclined surface located above the first inclined surface,
The solid fuel pulverization apparatus according to any one of claims 1 to 6, wherein an inclination angle of the first inclined surface with respect to a horizontal direction is larger than an inclination angle of the second inclined surface with respect to the horizontal direction. The seal member has a plurality of convex portions each formed with the inclined surface,
Among the plurality of convex portions, the inclination angle of the inclined portion with respect to the horizontal direction of the inclined surface of the convex portion arranged closest to the space after the blade classifies the solid fuel, the blade is the solid fuel. The solid fuel pulverization apparatus according to any one of claims 1 to 6, wherein an inclination angle of the inclined surface with respect to a horizontal direction of the convex portion arranged on the side leading to the space before classification is smaller than the horizontal direction.   The solid fuel pulverizing apparatus according to any one of claims 1 to 7, wherein at least a surface of the gap facing the seal member is flat. In a solid fuel pulverizer having a rotary classifier,
The rotary classifier includes a plurality of blades that are provided so as to be rotatable with respect to the coal supply pipe and classify the pulverized solid fuel, a frame body disposed above the plurality of blades, and the frame body. An opposing member facing in the circumferential direction,
Between the frame and the opposing member, a space is formed that communicates the space after the blade classifies the solid fuel and the space before the blade classifies the solid fuel, and bypasses the blade. And
Projecting from either one of the frame and the opposing member toward the gap, a seal member is provided,
The sealing member is an operation method of a solid fuel pulverization apparatus in which an inclined surface is formed on a space side after the blade classifies the solid fuel,
Injecting seal gas from the side that leads to the space after the blade classifies the solid fuel with respect to the seal member, and suppressing the pulverized solid fuel from passing through the gap;
An operation method of a solid fuel pulverizing apparatus, comprising the step of introducing the solid fuel into the rotary classifier by transfer air.

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