JP2013180231A - Pulverizer and pulverizing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulverizer that prevents wear and damage of a drift plate, and that can improve strength of an oxidizing gas jet ring.SOLUTION: A drift vane 53 of an oxidizing gas jet ring 50 is formed such that a ridge line 53a of an intermediate part is bent as a bend section having a cross-section of a v-shape. As a result, the drift vane 53 consists of a drift vane lower part 53A between a lower end face 53b and the ridge line 53a, and a drift vane upper part 53B between the ridge line 53a and an upper end face 53c, and has a shape such that the drift vane upper part 53B is twisted to a radial direction inside to the drift vane lower part 53A. The oxidizing gas jet ring 50 is provided, and thereby an oxidizing gas for conveyance is sent off to be twisted toward a center of a casing.

Description

  The present invention relates to a pulverizer and a pulverizing method for pulverizing a solid fuel such as coal in a coal-fired thermal power plant with a roller.

  Conventionally, coal-fired boilers use pulverized coal pulverized by putting raw coal into a pulverizer. Inside the pulverizer, the raw coal is pulverized, and the pulverized pulverized coal is dried and classified. Is done.

  As shown in FIG. 1, the pulverizer 10 receives raw coal falling from the coal supply pipe 2, and is driven to rotate around a vertical axis by a motor 3a, and a roller 4 that crushes the raw coal on the table 3, And a classifying unit 6 for classifying the pulverized charcoal crushed by the roller 4.

In such a pulverizer 10, as a method of conveying pulverized pulverized coal to a boiler from a pulverized coal pipe provided in the pulverizer, air current conveyance using an oxidizing gas such as air is used.
In the casing 5, a supply port 5 a for taking in an oxidizing gas for airflow conveyance from the outside is provided in the lower part of the casing 5. The oxidizing gas supplied into the casing 5 from the supply port 5 a flows out from the annular oxidizing gas blowing ring 7 provided on the outer periphery of the table 3 into the upper space of the table 3 and is crushed on the table 3. The charcoal is conveyed to the upper classification unit 6. In the classifying unit 6, during operation of the pulverizer 10, only pulverized coal particles pass through the classifying unit 6 and flow out from the powder outlet 8 and are classified.

  Here, as shown in FIG. 5, the oxidizing gas blowing ring 7 includes an inner annular wall 7a and an outer annular wall 7b that form an annular oxidizing gas passage, and the inner annular wall 7a and the outer annular wall 7b. A plurality of vanes 7c are provided between the two. The vane 7c is provided such that the upper end 7e is offset in the circumferential direction with respect to the lower end 7d and is inclined in the circumferential direction. By the vanes 7 c, a spiral airflow can be generated in the space above the oxidizing gas blowing ring 7, and the pulverized coal rises while swirling and is uniformly fed into the classification unit 6.

  Further, as shown in FIG. 1, a drift plate 9 is provided above the oxidizing gas blowing ring 7 so as to drift the airflow toward the central portion in the casing 5. As a result, the oxidizing gas blown out from the oxidizing gas blowing ring 7 hits the drift plate 9 and is directed toward the central portion by the inclined portion of the drift plate lower surface, where pulverized coal having a certain particle size falls on the table and is primarily classified. Thus, only the pulverized charcoal having a small particle diameter can be efficiently fed into the classifying unit 6.

  However, there is a problem that the air blown up from the oxidizing gas blowing ring 7 and entrained with pulverized charcoal collides with the drift plate 9 and wears the drift plate 9. The drift plate 9 is made of a material that does not easily wear. However, this problem cannot be avoided when the plate 9 is worn by long-term use or when hard foreign matter is mixed in the raw coal. Further, when the drift plate 9 is worn down to the mounting bolt for attaching to the casing 5, the drift plate 9 falls off and the pulverizer 1 has to be stopped.

  Therefore, Patent Document 1 discloses a drift ring that extends the life by minimizing the wear of the drift plate 9 where the transporting oxidizing gas collides while maintaining the classification performance, and drifts the oxidizing gas toward the center of the ring. Has been proposed in which the outer ring wall 7b is provided.

JP 2007-209838 A

  However, above the oxidizing gas blowing ring 7, the pulverized coal is scattered on the outer peripheral side of the table 3 due to the centrifugal force accompanying the rotation of the table 3. On the other hand, the above-mentioned oxidizing gas blowing ring 7 only blows the oxidizing gas vertically, and the force for returning the coal scattered on the outer peripheral side to the center of the crusher is weak and hits the drift plate located above. In this state, the pulverized charcoal scattered on the outer peripheral side of the table 3 cannot be strongly biased so as to be reliably conveyed toward the inner peripheral side of the table 3.

Moreover, since the conventional vane 7c is flat, it is easy to bend and the strength against deformation may not be sufficient.
In the pulverizer 10, the roller 4 is pulverized by sandwiching the raw coal between the roller 4 and the table 3 while rotating by friction with the raw coal on the rotating table 3. At this time,
Since the roller 4 is pressed against the table 3 by a pressurizing mechanism such as a hydraulic cylinder, when the roller 4 moves up and down according to the coal layer when the raw coal on the table 3 is pulverized, the reaction force is applied to the hydraulic cylinder or the like. It is transmitted to the casing 5 of the pulverizer 10 through the pressurizing mechanism. Then, the whole grinder 10 vibrates.
The vibration generated by the vertical movement of the roller 4 includes a vibration that is constantly generated and an abnormal vibration that is generated by self-excited vibration when the roller 4 slips between the raw coal on the table 3. The self-excited vibration of the roller 4 is generated when the roller 4 pulverizes raw coal and the roller 4 slips in the lateral direction (direction along the rotation axis), and thereafter, recovery of friction and slip are repeated. When slip occurs in the roller 4 due to such self-excited vibration, a large abnormal vibration such as an impact is generated on the roller 4. When such abnormal vibration is transmitted to the casing 5 of the pulverizer 10, the vane 7c may be deformed or cracked.

  The present invention has been made in view of such circumstances, and it is intended to provide a pulverizer and a pulverization method thereof that can prevent the wear and damage of the drift plate and increase the strength of the oxidizing gas blowing ring. Objective.

In order to solve the above problems, the pulverizer and the pulverization method of the present invention employ the following means.
A casing, a table that is driven to rotate in the casing, a roller that rotates while being pressed by the upper surface of the table, and that grinds the object to be crushed on the table, and is attached to the outer periphery of the table in the casing An oxidizing gas blowing ring, and a drift plate attached above the oxidizing gas blowing ring and inclined toward the center of the casing, the oxidizing gas blowing ring comprising an inner annular wall forming an annular oxidizing gas passage and An outer annular wall, and a plurality of drift vanes provided between the inner annular wall and the outer annular wall at a distance in the circumferential direction of the oxidizing gas blowing ring. The inner ring at the lower side of the drift vane so that the oxidant gas fed into the oxidant gas blowing ring from below is drifted toward the center of the casing. The upper end surface connecting the inner annular wall and the outer annular wall on the upper side of the drift vane is inclined toward the center side of the oxidizing gas blowing ring with respect to the lower end surface connecting the outer annular wall and the outer annular wall. It is provided.

  Such a drift vane can cause the oxidizing gas fed from below to the oxidizing gas blowing ring to drift toward the center of the casing, whereby the crushed material crushed by the roller on the table hits the drift plate. Can be prevented.

  It is preferable that the drift vane has a three-dimensional shape having a bent portion between the lower end surface and the upper end surface. This increases the strength of the drift vane.

  Furthermore, in the pulverizing method of the pulverizer according to the present invention, a casing, a table that is driven to rotate in the casing, a roller that rotates while being pressed against the upper surface of the table, and pulverizes the object to be crushed on the table, An oxidizing gas blowing ring attached to the outer periphery of the table in the casing, and a drift plate attached above the oxidizing gas blowing ring and inclined toward the center of the casing, the oxidizing gas blowing ring being annular A plurality of inner annular walls and outer annular walls forming the oxidizing gas passage, and a plurality of circumferentially spaced portions of the oxidizing gas blowing ring are provided between the inner annular wall and the outer annular wall. A drift vane, wherein the drift vane connects the inner annular wall and the outer annular wall at a lower side of the drift vane. An upper end surface connecting the inner annular wall and the outer annular wall on the upper side of the drift vane with respect to the surface is provided to be inclined toward the center side of the oxidizing gas blowing ring. The oxidizing gas fed into the oxidizing gas blowing ring is supplied while being drifted toward the center of the casing.

The pulverized coal formed by the rollers is transported upward by the oxidant gas introduced from the oxidant gas blowing ring on the outer peripheral side of the table. However, it is conveyed to the outside.
As a result, the oxidizing gas blown upward from the oxidizing gas blowing ring is strongly biased toward the inside of the casing, and the pulverized coal that tends to flow to the outer peripheral side by centrifugal force when the table rotates is less likely to collide with the drift plate. . As a result, wear and damage of the drift plate can be prevented, and high durability is achieved.

The drift vane causes the oxidizing gas to drift toward the center of the casing, thereby preventing the pulverized product crushed by the roller on the table from colliding with the drift plate. As a result, wear and damage to the drift plate can be prevented.
In addition, by forming the drift vane into a three-dimensional shape in order to cause the oxidizing gas to drift toward the center of the casing, the strength can be increased and the strength of the oxidizing gas blowing ring can be increased.

It is sectional drawing which shows the whole structure of the grinder which is an example of the grinder of this invention. It is a perspective view which shows a part of circumferential direction of the oxidizing gas blowing ring in this invention. It is sectional drawing and a top view of an oxidizing gas blowing ring. It is a figure which shows an oxidizing gas blowing ring and a drift plate. It is a perspective view which shows a part of circumferential direction of the oxidizing gas blowing ring of the conventional this invention.

Hereinafter, an embodiment of a crusher and a crushing method thereof according to the present invention will be described with reference to the drawings.
Hereinafter, an embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, a pulverizer 10 includes a pulverizing unit 20 that pulverizes coal into pulverized coal in a cylindrical casing 11 that forms an outer shell, and a classification unit 30 that classifies the particle size of the pulverized coal. And. Above the casing 11, a coal supply unit 15 that supplies coal supplied from the outside, such as a coal storage, into the casing 11 is disposed.
On the upper surface of the casing 11, there are provided a coal supply pipe 12 that sends coal into the casing 11 from the coal supply section 15, and a plurality of pulverized coal pipes 13 that send the pulverized coal classified by the classification section 30 to the outside. ing.

  The coal supply unit 15 has a configuration in which a conveyor unit 17 that conveys coal supplied from the outside to the inlet of the coal supply pipe 12 is provided in a casing 16 that forms an outer shell of the coal supply unit 15. Seal air is introduced into the casing 16.

  The crushing unit 20 crushes the coal on the table 21 into a pulverized coal by crushing the disk on the disk-like table 21 to which the raw coal is supplied from the coal supply pipe 12, the motor 23 that rotates the table 21 around the vertical axis. A roller mechanism (roller) 24 is provided.

  Above the outer peripheral portion of the table 21, a drift plate 25 that drifts the airflow toward the center in the casing 11 is provided. Thereby, an airflow comes to a center part and the pulverized charcoal can be efficiently sent now to the classification part 6. FIG.

  In the casing 11, a supply port 18 for taking in an oxidizing gas for airflow conveyance from the outside is provided in the lower portion of the casing 11. The oxidizing gas supplied from the supply port 18 into the casing 11 flows into the upper space of the table 21 and conveys the pulverized charcoal crushed on the table 21 to the upper classification unit 30. Here, an annular oxidizing gas blowing ring 50 is provided between the casing 11 and the outer peripheral portion of the table 21.

  Here, as shown in FIGS. 2 and 3, the oxidizing gas blowing ring 50 is integrally provided on the outer peripheral portion of the table 21. The oxidizing gas blowing ring 50 includes an inner annular wall 51 of a double ring-shaped belt-shaped ring that forms an annular oxidizing gas passage, and a cylindrical outer side provided concentrically on the outer peripheral side of the inner annular wall 51. It has a configuration including an annular wall 52 and a drift vane 53 provided between the inner annular wall 51 and the outer annular wall 52.

A plurality of drift vanes 53 are provided at intervals in the circumferential direction of the oxidizing gas blowing ring 50.
Each drift vane 53 is formed by bending a plate-like member into a dogleg shape with an intermediate ridge line 53a as a bent portion. The lower end surface 53 b of the drift vane 53 is provided so as to connect the lower end portion 51 a of the inner annular wall 51 and the lower end portion 52 a of the outer annular wall 52 in the radial direction of the oxidizing gas blowing ring 50. The ridge line 53a is formed so as to be gradually lowered from the inner annular wall 51 side toward the outer annular wall 52 side. In addition, the edge 53d on the outer annular wall 52 side is positioned more forward in the rotational direction of the oxidizing gas blowing ring 50 that rotates integrally with the table 21 than the end 53e on the inner annular wall 51 side. It is formed to do. Accordingly, the distance between the end 53e on the inner annular wall 51 side and the lower end surface 53b is larger than the distance between the end 53d on the outer annular wall 52 side and the lower end surface 53b.
The upper end surface 53 c of the drift vane 53 is provided so as to connect the upper end portion 51 b of the inner annular wall 51 and the upper end portion 52 b of the outer annular wall 52. Further, the upper end surface 53c has an end 53f on the outer annular wall 52 side at the rear side in the rotation direction of the oxidizing gas blowing ring 50 that rotates integrally with the table 21 rather than an end 53g on the inner annular wall 51 side. It is formed to be located. Thereby, the drift vane 53 is provided with the upper end surface 53c inclined toward the center side of the oxidizing gas blowing ring 50 with respect to the lower end surface 53b.
Such a vane 53 includes a drift vane lower portion 53A between the lower end surface 53b and the ridge line 53a and a drift vane upper portion 53B between the ridge line 53a and the upper end surface 53c. The upper portion 53B has a shape that is twisted (twisted) radially inward.

By providing such an oxidizing gas blowing ring 50, the oxidizing gas supplied into the casing 11 from the supply port 18 at the lower part in the casing 11 passes through the oxidizing gas blowing ring 50 that rotates integrally with the table 21, and the table 21. The crushed charcoal is conveyed to the classifying unit 30.
The oxidizing gas blowing ring 50 has a shape in which the drifting vane 53 is twisted radially inward with respect to the drifting vane lower part 53A. Oxidizing gas is sent out by the ring 50 so as to be twisted toward the center of the casing 11. Thereby, as shown in FIG. 4, the oxidizing gas of the present invention flows without colliding with the drift plate 25.

In such a pulverizer 10, the coal sent from the outdoor or indoor coal storage is conveyed to the coal supply pipe 12 by the conveyor unit 17 of the coal supply unit 15. The coal that has passed through the coal supply pipe 12 is supplied to the table 21 of the crushing unit 20 and is arranged on the table 21. The raw coal placed on the table 21 is crushed by the roller mechanism 24 of the crushing unit 20 while rotating together with the table 21 to become pulverized coal.
The pulverized coal formed by the roller mechanism 24 is conveyed upward by the oxidizing gas introduced from the oxidizing gas blowing ring 50 on the outer peripheral side of the table 21, and in the classification unit 30, the pulverized coal having a predetermined particle size or less is passed, It flows into the pulverized coal pipe 13 and is conveyed to the outside.

As a result, the oxidizing gas blown upward from the oxidizing gas blowing ring 50 is strongly biased toward the inside of the casing 11, and the pulverized coal that tends to flow to the outer peripheral side by the centrifugal force when the table 21 rotates is applied to the drift plate 25. It becomes difficult to collide. As a result, wear and damage to the drift plate 25 can be prevented and high durability is achieved.
Further, the drift vane 53 has such a shape that the drift vane lower part 53A and the drift vane upper part 53B are bent at the ridge line 53a, and therefore the rigidity is greatly increased as compared with a flat plate shape. be able to. As a result, even if self-excited vibration or the like due to the slip of the roller occurs in the roller mechanism 24, the drift vane 53 can be prevented from being deformed, and high reliability can be achieved.

In addition, in the said embodiment, if the structure of each part of the grinder 10 does not deviate from the main point of this invention, it can be changed into another structure suitably.
For example, the drift vane 53 has a three-dimensional shape bent at the ridge line 53a, but may have a continuous curved shape from the lower end surface 53b toward the upper end surface 53c.
Furthermore, even if it is except the crusher 10 which grind | pulverizes coal, if the grinder grind | pulverizes the to-be-ground material on a table with a roller, the said structure is applicable similarly.

DESCRIPTION OF SYMBOLS 10 Crusher 11 Casing 12 Coal supply pipe 13 Pulverized coal pipe 15 Coal supply part 16 Casing 18 Supply port 20 Crushing part 21 Table 24 Roller mechanism (roller)
25 Diffusion plate 30 Classifying part 50 Oxidizing gas blowing ring 51 Inner ring wall 52 Outer ring wall 53 Drift vane 53A Drift vane lower part 53B Drift vane upper part 53a Ridge (bent part)
53b Lower end surface 53c Upper end surface

Claims (3)

A casing,
A table that is rotationally driven in the casing;
A roller that rotates while being pressed against the upper surface of the table and crushes the object to be crushed on the table;
An oxidizing gas blowing ring attached to the outer periphery of the table in the casing;
A drift plate attached above the oxidizing gas blowing ring and inclined toward the center of the casing,
The oxidizing gas blowing ring includes an inner annular wall and an outer annular wall forming an annular oxidizing gas passage, and a circumferential direction of the oxidizing gas blowing ring between the inner annular wall and the outer annular wall. A drift vane provided with a plurality at intervals, and
The drift vane has a lower end surface connecting the inner annular wall and the outer annular wall at the lower side of the drift vane so that the oxidizing gas fed from below into the oxidizing gas blowing ring drifts toward the center of the casing. On the other hand, an upper end surface connecting the inner annular wall and the outer annular wall on the upper side of the drift vane is provided so as to be inclined toward the center side of the oxidizing gas blowing ring. .   The pulverizer according to claim 1, wherein the drift vane has a three-dimensional shape having a bent portion between a lower end surface and an upper end surface. A casing,
A table that is rotationally driven in the casing;
A roller that rotates while being pressed against the upper surface of the table and crushes the object to be crushed on the table;
An oxidizing gas blowing ring attached to the outer periphery of the table in the casing;
A drift plate attached above the oxidizing gas blowing ring and inclined toward the center of the casing,
The oxidizing gas blowing ring includes an inner annular wall and an outer annular wall forming an annular oxidizing gas passage, and a circumferential direction of the oxidizing gas blowing ring between the inner annular wall and the outer annular wall. A drifting vane provided with a plurality at intervals, and a pulverizing method for a pulverizer,
The drift vane connects the inner annular wall and the outer annular wall on the upper side of the drift vane to a lower end surface connecting the inner annular wall and the outer annular wall on the lower side of the drift vane. An upper end surface is provided to be inclined toward the center side of the oxidizing gas blowing ring,
A pulverizing method for a pulverizer, characterized in that an oxidant gas fed from below to an oxidant gas blowing ring is caused to drift toward the center of the casing by the drift vane.

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