JP2000107619A - Vertical roller mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a method of uniting a group of coal particles at the outlet of a pulverizing part in the upper part of a throat and primary air to better comprehensive mill performance. SOLUTION: This roller mill is provided with a pulverizing part consisting of a pulverizing table 2 and a pulverizing roller 3 installed in the lower part of a housing 7 and a group of air introducing throats 4 arranged on the outer periphery of the pulverizing table 2, and it is set so that the velocity component in the peripheral direction of the pulverizing table 2 of air jetted from the air introducing throats 4 is reverse to the direction of the peripheral velocity at the outer peripheral end of the pulverizing table 2. In this case, on the outer peripheral part of the pulverizing table 2, plural partition members 200 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical roller mill for producing a fine powder having a predetermined particle size by pulverizing a raw material such as coal, and more particularly to a structure of a roller mill in which the flow state in the mill is improved.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view showing a schematic configuration of a vertical roller mill used as a pulverized coal feeder of a coal fired boiler system which has been conventionally implemented. In the figure, a vertical roller mill is provided with a coal feed pipe 1 for supplying raw coal as an object to be crushed into an apparatus from an upper part and a crusher 5 on a lower side.
And a classifier 6 on the upper side.

The pulverizing section 5 has a pulverizing table 2, a pulverizing roller 3, and a throat 4 as a primary air inlet disposed inside a housing 7 at a lower portion of the main body. The classifying unit 6 includes a fixed classifying unit 10 and a rotary classifying unit 20. The fixed classifier 10 is arranged at the upper part of the main body, and the rotary classifier 20 is arranged inside the fixed classifier 10. .

[0004] As shown in FIG. 8, a throat 4 of the pulverizing section 5 includes a fixed throat 41 fixed to the housing 7 side,
As shown in FIG. 10, a rotating throat 42 fixed to the outer peripheral portion of the grinding table 2 and rotating with the grinding table 2.
Are known. The direction of air discharge from the rotary throat 42 is also determined by the grinding table 2.
Are known in which the elevation angle is set in the rotation direction and the one in which the elevation angle is set in the reverse rotation direction. 9 is the same as FIG.
11 is a cross-sectional view taken along the line CC of FIG. 10, and FIG. 11 is a cross-sectional view taken along the line DD of FIG. 10. Throat ports 411, 421 separated by throat fins 412, 422 are formed. The next air blows out to the top of the throat 4.

The classifying section 6 includes a cyclone-type fixed classifier 10 alone, a rotary classifier 20 only, and a combination of both as shown in FIG. There are three known formats. Hereinafter, the operation and the flow of particles and air in the mill will be described based on the type shown in FIG.

Raw coal (coal) 100 as a material to be pulverized supplied from the coal feed pipe 1 falls to the center of the rotating pulverization table 2 and is centrifugally generated by the rotation of the pulverization table 2 to cause the pulverization of the pulverization table 2. It draws a spiral locus above and moves to the outer periphery. The raw coal which has moved to the outer peripheral portion is guided between the pulverizing table 2 and the pulverizing roller 3, and is caught between the two to be pulverized. The pulverized coal further moves to the outer periphery, and collides with primary air heated to 150 to 300 ° C., which is jetted from a throat 4 provided around the pulverization table 2,
While being dried, it is blown up and guided to the classification section 6. Turning blade 1 of fixed classifier 10 from throat 4
The section up to the lower end of 2 is called a primary classification section 61, and the blown-up particles are subjected to classification by gravity, so that coal powder having a coarse particle diameter falls and is returned to the pulverization section 5. Therefore, the classification in the primary classification section 61 is referred to as primary classification.

The fine coal powder that has reached the classification section 6 is classified into fine coal having a predetermined particle size or less and coarse coal having a predetermined particle size or more by a fixed classifier 10 and a rotary classifier 20.
The coarse coal is dropped along the inner wall of the cone portion 11 by gravity, and is reground by the grinding table 2 and the grinding roller 3. On the other hand, the pulverized coal wound by the rotating blades 21 is sent out to a burner of a boiler (not shown) through a coal feeding pipe 30. Therefore, the classification in the classification unit 6 after the primary classification is referred to as a secondary classification with respect to the primary classification, and a portion performing the secondary classification is referred to as a secondary classification unit 62.

[0008] By classifying in the primary and secondary classifying sections 61 and 62, the raw coal charged into the mill is recirculated in the mill and sent out of the mill, so that the retained coal is stored in the mill. The resulting fluidized bed and moving bed are formed. In particular, a portion 400 directly above the throat 4 includes a group of coal particles from the outlet of the pulverizing section 5, that is, raw coal moving from the pulverizing table 2 and return coal from the primary and secondary classification sections 61 and 62. This is a region where the mixture of the pulverized coal newly pulverized by the pulverizing table 2 and the pulverizing roller 3 joins with the primary air. Since this region serves as an entrance of the classifying section 6 located in the downstream flow, the flow state in this region greatly affects the performance of classification.

In order to make the flow state in this region a desired state, many structures of the pulverizing table 2 and the throat 4 are devised, and the structure relating to the throat 4 side relates to the structure relating to the pulverizing table 2 side. More and more. As a typical example, an example in which the throat itself is fixed and rotated, such as a fixed throat and a rotating throat, and the speed component in the circumferential direction of the pulverization table 2 of the air injection speed for each of both throats is the rotation of the pulverization table 2 There is an example of setting in the forward direction and the reverse direction with respect to the direction.

As related techniques, for example, JP-A-6-277539, JP-A-9-225329, JP-A-9-234381, and JP-B-7-83.
The inventions described in Japanese Patent No. 839 and Japanese Patent No. 25512376 are known.

[0011]

However, in the above-mentioned prior art, the process of merging the coal particles at the outlet of the pulverizing section from the pulverizing table 2 to the outer periphery of the table by centrifugal force and the primary air introduced from the throat 4 is described. No consideration is given, and there is a variation in particle concentration distribution (drift) in the circumferential direction of the housing in the upper part of the throat 400, which tends to be non-uniform due to the presence of a plurality of rollers, or a pulverization that is an aggregate of particles having different particle size distributions. There was a problem such as a variation in the degree of confusion in the coal particle group at the outlet (mixture of raw coal, returned coal, and newly generated pulverized coal), that is, poor so-called dispersibility.

[0012] These problems occur downstream of the throat section.
In terms of position, it is the main cause of the decrease in the classification performance in the primary and secondary classification sections located above, and the influence on the mill performance specified by the particle size distribution, power, differential pressure, stable operation, etc. is large. I was

The present invention has been made in view of the above problems, and an object of the present invention is to improve a method of combining coal particles at the outlet of a pulverizing section and primary air in the upper part of the throat,
The aim is to achieve uniform particle concentration (suppress drift) and promote mixing of particle groups (improve dispersibility) to achieve overall mill performance (particle size distribution,
Power, differential pressure, and stable operation).

[0014]

In order to achieve the above object, a first means comprises a pulverizing table and a pulverizing roller provided at a lower portion in a housing, and a throat for air introduction disposed at an outer periphery of the pulverizing table. And a crushing unit comprising a crushing unit, and a speed component of air injected from the air introduction throat in a circumferential direction of the crushing table is set to be opposite to a direction of a circumferential speed at an outer peripheral end of the crushing table. In the vertical roller mill described above, a plurality of partition members are provided on an outer peripheral portion of the crushing table.

The second means is characterized in that, in a vertical roller mill on the same premise, the upper surface of the outer peripheral portion of the crushing table is arranged to be higher than the upper surface of the air introduction throat group.

According to a third aspect, in the second aspect, a plurality of partition members are provided on an outer peripheral portion of the crushing table.

The fourth means is provided with a pulverizing section comprising a pulverizing table and a pulverizing roller provided at a lower portion in the housing, and a throat group for air introduction disposed at an outer periphery of the pulverizing table. In a vertical roller mill set so that the velocity component of air injected from the throat in the circumferential direction of the crushing table is opposite to the direction of the circumferential speed at the outer peripheral end of the crushing table, the peripheral speed of the crushing table is A gas nozzle or a liquid nozzle for injecting a gas or a liquid having the same flow direction as the direction is provided on an outer peripheral portion of the crushing table.

The fifth means is provided with a pulverizing section comprising a pulverizing table and a pulverizing roller provided at a lower portion in the housing, and a throat group for air introduction disposed at an outer periphery of the pulverizing table. In a vertical roller mill set so that the velocity component of air jetted from the throat in the circumferential direction of the crushing table is opposite to the direction of the peripheral speed at the outer peripheral end of the crushing table, the inner circumference of the crushing roller is A plurality of partition members are radially installed on the grinding table on the side with respect to the rotation axis of the grinding table.

[0019] With this configuration, a sufficient momentum can be secured by the particle group itself just before the coal particle group at the outlet of the pulverizing section joins the primary air at the upper part of the throat. As a result, the scale of the collision between the coal particles at the outlet of the pulverizing section and the primary air is increased, so that a local particle retention area which the vertical roller mill has as its own structural characteristic is not formed. , And a coal particle group at the outlet of the pulverizing section (raw coal,
The return coal and the newly formed pulverized coal) are not sufficiently mixed and do not flow into the primary and secondary classification sections downstream of the pulverization section outlet.

Furthermore, the fact that there is a region where the drift is high, that is, the region where the particle concentration is high, and that the degree of low mixing, that is, that the particles are not evenly mixed and the particle size distribution is locally different, are as follows.
Since it is an obstacle to perform classification with high accuracy, the above-described obstacle can be eliminated by configuring as described above.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same parts as those in the above-described conventional example are denoted by the same reference numerals, and overlapping description will be omitted.

<First Embodiment> FIG. 1 is a sectional view showing the structure of a vertical roller mill according to a first embodiment of the present invention, and FIG. 2 (1) is an enlarged view of a main part showing a throat portion of FIG. Sectional view,
2 (2) is a plan view of the throat portion and the outer peripheral portion of the pulverizing table of the vertical roller mill of FIG. 1, and FIG. 3 is a sectional view taken along line AA in FIG. 2 (1).

In this embodiment, a plurality of partition members are provided on the upper surface side of the outer periphery of the grinding table 2 of the conventional example shown in FIG.
As an example, a partition fin 200 (hereinafter, referred to as a partition fin as an example of a partition member) is erected, and the other configuration is the same as the conventional example shown in FIG.
The description here is omitted.

The throat structure of this embodiment is a so-called rotary throat in which a throat group is attached to the crushing table 2 and is rotated together with the crushing table. The direction of the horizontal component VPA · cos θ (VPA: primary air flow rate, θ: discharge elevation angle) of the primary air flow rate and the outer peripheral end 2 of the crushing table 2
The direction (rotation direction) of the peripheral speed Vω at 01 is set to be opposite to each other as shown in FIG. That is, the primary air is supplied to the throat port 42 as shown in FIG.
1, the jet is ejected at an elevation angle θ with a velocity component in the direction opposite to the rotation direction T of the crushing table 2, so that the direction is opposite to the direction of the peripheral speed Vω of the crushing table 2.

Under such a configuration, the raw coal 100 supplied from the coal feed pipe 1, the return coal 101 sliding down the inner wall of the cone portion 11, and the new generation pulverized between the roller 3 and the pulverization table 2 The charcoal 103 receives centrifugal force due to the rotation ω of the crushing table 2 and moves toward the outer peripheral end 201 of the crushing table 2. In the process of moving the crushing table 2 to the outer peripheral end 201 side, the velocity component of the coal particles in the circumferential direction of the crushing table 2 is caused by slip between particles inside the particle group and wall slip between the particles and the crushing table 2. The speed is reduced, and reaches the outer peripheral end 201 of the crushing table 2 while being slower than the circumferential speed of the crushing table 2. Particles reaching the outer peripheral end 201 of the pulverizing table 2 or particles just before reaching the outer peripheral end 201 pass between the partition fins 200 or exist between the fins 200 but exist between the fins 200. During this period, the position in the circumferential direction is defined by the fins 200, so that relative movement in the circumferential direction is restricted. for that reason,
As a result, it rotates together with the crushing table 2, so that the same velocity Vω as the peripheral velocity of the outer peripheral end 201 of the crushing table can be obtained.

As described above, the speed component of the primary air in the circumferential direction of the pulverizing table 2 is Vpa · cos θ, and the direction of the speed is 180 ° different from the circumferential component Vω of the coal particles. The coal particles and the air collide violently, and the coal particles are well loosened in the upper part 400 of the throat 4, the drift of the coal particles in the circumferential direction of the housing 7 is suppressed, and the different particle size distribution merged in the pulverizing section 5 is obtained. Mixing and dispersion of the particle groups are efficiently performed. The particles in which the drift is suppressed and the mixing is promoted are mixed in the primary classification unit 61.
, To the secondary classification section 62, and after being subjected to a predetermined classification, is sent out to the mill outlet.

As described above, the partitioning fins 200 are provided on the crushing table 2 and the direction of the horizontal component of the primary air flow rate and the direction (rotation direction) of the peripheral speed Vω at the outer peripheral end 201 of the crushing table 2 are opposite to each other. With such settings, the coal particles and the air collide violently, the drift of the coal particles is suppressed, and the particles having different particle size distributions joined in the pulverizing unit 5 are efficiently mixed and dispersed, and the classification is efficiently performed. It can be carried out.

That is, according to the present embodiment, since a plurality of partition fins 200 are provided on the outer peripheral portion of the crushing table 2, particles reaching the classifier 6 via the outer circumference of the crushing table 2 are converted into particles by the speed of rotation of the crushing table 2. The components can be reliably transmitted, and can collide with the primary air with a sufficient horizontal momentum. As a result, the drift of the particle group in the housing circumferential direction in the upper part of the throat 400 is suppressed, and the mixing and dispersion of the coal particle group at the pulverizing section outlet in the pulverizing section 5 are increased, so that the primary and secondary classification sections 6
Classification of 1,62 becomes sharp and throat 4
It is possible to prevent uneven wear in the circumferential direction of the housing itself or the inner surface of the housing 7. In particular, the sharpening of the classification means that the coarse powder is surely returned to the pulverizing unit 5 and the fine powder is surely passed out of the mill (coal feed pipe). Therefore, the mill has the following characteristics. Will be.

(1) The ratio of crude coal in the pulverized coal at the mill outlet can be reduced.

(2) Since the useless circulation in the mill is reduced, the amount of retained coal is reduced, and as a result, the mill differential pressure and the grinding power can be reduced. The internal circulation in the mill refers to a phenomenon in which fine fine powder that should be discharged outside the mill is mixed with the coarse coal and returned to the pulverizing section in the mill.

(3) Since the amount of fine powder staying in the pulverizing portion, which causes unstable behavior of the pulverizing roller, is reduced, stable operation is possible.

In addition, since the amount of coal that normally falls to the lower side of the throat 4 and is discarded by the suppression of the drift is reduced, the primary air amount and the throat differential pressure can be reduced in addition to the effect of reducing the dropped coal. Becomes It should be noted that a reduction in the amount of primary air leads to a reduction in fan power and an improvement in the particle size of the fine powder at the mill outlet.

<Second Embodiment> FIG. 4 is a sectional view showing the structure of a vertical roller mill according to a second embodiment of the present invention, and FIG. 5 is an enlarged sectional view of a main part showing a throat portion in FIG. 6 is a sectional view taken along line BB in FIG.

In this embodiment, the height of the upper end surface 202 of the conventional crushing table 2 shown in FIG.
It is characterized by being higher than the upper end surface 401 of the
Other configurations are the same as those of the above-described conventional example and the first embodiment, and thus description thereof will be omitted.

The throat structure of this embodiment is a so-called rotary throat 42 in which a throat group is mounted on the crushing table 2 side and is rotated together with the crushing table 2.

Under this configuration, the raw coal 100 supplied from the coal feed pipe 1, the return coal 101 sliding down the inner wall of the cone portion 11, and the newly produced coal pulverized between the roller 3 and the pulverizing table 2 The charcoal 103 receives centrifugal force due to the rotation ω of the crushing table 2 and moves toward the outer peripheral end 201 of the crushing table 2. In the process of moving the crushing table 2 to the outer peripheral end 201 side, the velocity component of the coal particles in the circumferential direction of the crushing table 2 is caused by slip between particles inside the particle group and wall slip between the particles and the crushing table 2. The outer peripheral edge 20 of the crushing table 2 moves while being slowed down and slower than the circumferential speed of the crushing table 2.
Reach 1

The particles moving toward the outer periphery receive the drag N and the gravity mg from the crushing table 2 in the vertical direction.
Since the two are statically balanced, the vertical movement of the particles is small. However, the particles may not move
, The drag N disappears and the particles receive only the mg of gravity. Actually, since the vertically upward component of the primary air is applied outside the outer peripheral end 202 of the crushing table 2, on average, the particles move vertically upward due to the unbalance between the drag and the gravity due to the primary air. To go. However, since the air and the particles mutually interfere with each other, the air flow velocity fluctuates microscopically, and the particles are moved to the upper end surface 401 of the throat 4.
To fall. In the course of this drop, the particles have a downward velocity Vg. Since the velocity Vg is opposite to the vertical component Vpa · sin θ of the primary air flow velocity, the particles collide with the air here. Due to this collision, the drift of the particles is suppressed, and at the same time, the mixing and dispersion are promoted.

As described above, the second embodiment is different from the first embodiment in that the collision between particles and air is horizontal, whereas the collision between particles and air is vertical. Although different, the effect achieved is the same as that of the first embodiment.

<Third Embodiment> Next, as a third embodiment, the first embodiment and the second embodiment are combined, and the upper end surface 2 of the grinding table 2 in the second embodiment is combined.
02, the partition fins 200 according to the first embodiment may be erected so that the collision between particles and air is performed in both the horizontal direction and the vertical direction. In this case, the collision in the horizontal direction and the collision in the vertical direction occur simultaneously, so that the effect of suppressing the drift of the particles and the effect of promoting the mixing and dispersion can be synergistically obtained.

In the first and second embodiments, the throat structure is a rotary throat, but the same effect can be obtained even in the case of the fixed throat shown in FIG. The choice is a matter of design.

Further, the partitioning fin 200 removes the pulverized coal obtained by mixing the return coal 101 sliding down the inner wall of the cone portion 11 and the newly generated coal 103 pulverized between the roller 3 and the pulverization table 2 to the outside of the pulverization table 2. In consideration of the discharge efficiency, it is preferable that the strength is as thin as possible.

<Fourth Embodiment> A fourth embodiment of the present invention corresponds to the partition member of the first embodiment, and includes a plurality of gas nozzles or liquid nozzles on the upper surface side of the outer periphery of the crushing table 2. 108 is provided. As shown in FIG. 12, the gas or liquid ejected from the nozzle 108 acts to accelerate the peripheral velocity component of the coal particles on the outer periphery of the grinding table. Then, the deceleration of the coal particles is suppressed, and the coal particles violently collide with the air from the throat. As a result, the drift of the particles in the upper part of the throat in the circumferential direction of the housing is suppressed, and the mixing and dispersion of the particles are increased.

<Fifth Embodiment> In a fifth embodiment of the present invention, as shown in FIG. 12, a partitioning member, a scraper 109 as an example, includes a grinding roller 3 and a mill center (a rotation center of a grinding table). During this, it is installed radially on the crushing table 2. The partition members on the crushing table may be arranged evenly on the circumference, a plurality of partition thin plates may be arranged as a group, or a plurality of thin plates may be arranged as a group. According to this embodiment, the powder that has fallen to the rotation center of the crushing table follows the centrifugal force with the rotation of the crushing table and enters the partition member 109. The powder is surrounded by the partition member and centrifugal force acts at the rotation speed of the crushing table, passes through the gap between the crushing rollers (usually three crushing rollers rotate on the crushing table), and the upper part of the throat. And violently collides with the air from the throat, thereby suppressing powder drift.

Next, the results of experiments on the functions and effects of the vertical roller mill according to the embodiment of the present invention are shown in FIGS.
This will be described below with reference to FIG.

In FIG. 13 showing the effect of suppressing the drift, the horizontal axis indicates the position in the circumferential direction of the housing, and indicates the position corresponding to each roller when three crushing rollers are arranged at 120 ° intervals on the crushing table. And “between rollers” in the figure.
Represents an intermediate position with respect to an adjacent roller, and "roller" represents a rotational center position of the roller. Further, the coal seam pressure difference on the vertical axis is a pressure difference caused by the coal held in the mill, and is a pressure difference between the pressure at the upper part of the throat and the pressure at the inlet of the classifier.

According to the present invention, the particles reaching the classifier via the outer periphery of the grinding table reliably transmit the velocity component due to the rotation of the grinding table and collide with the primary air with a sufficient horizontal momentum or the gravity. As a result, the air impinges on the primary air with momentum in the vertical direction, so that the coal seam differential pressure corresponding to the roller rotation center position of the particle group in the upper part of the throat in the housing circumferential direction is reduced as compared with the conventional example. That is, a drift suppression effect is achieved.

In FIG. 14 showing the effect of improving the mixing / dispersion degree of the coal particles at the outlet of the pulverizing section, the horizontal axis represents the position in the circumferential direction of the housing, and the position corresponding to the three rollers arranged vertically. The axis indicates the mixing ratio of coarse particles into fine particles. According to the present invention, the degree of mixing / dispersion of the coal particles at the outlet of the pulverizing section (mixture of raw coal, return coal, and newly generated pulverized coal), which is an aggregate of particles having different particle size distributions in the pulverizing section, is a conventional example. It can be seen that it is increasing compared to. As a result, in addition to sharpening the classification of the primary and secondary classification portions, there is an effect that the throat itself and uneven wear of the inner surface of the housing in the circumferential direction of the housing can be prevented.

FIG. 15 shows the effect of sharpening the classification in the classification section. Classifying and sharpening means that the coarse powder is reliably returned to the pulverizing section and that the fine powder is reliably passed out of the mill (coal feed pipe). FIG. 15 shows this as a reduction in the powder ratio. In FIG. 15, the horizontal axis represents the passage rate of a screen of 75 μm, and the vertical axis represents the passage rate of a coarse screen of 150 μm. As can be seen from the drawing, according to the present invention, classification sharpening can be achieved as compared with the conventional example.

FIG. 16 shows the effect of reducing the mill differential pressure and the grinding power. The sharpening of the classification reduces the amount of waste coal in the mill (for example, fine fine powder that should be discharged to the outside of the mill is mixed with the coarse powder and returned to the crushing section in the mill). As a result, a reduction in the mill differential pressure and the grinding power was achieved, which is shown in FIG.

FIG. 17 shows the effect of expanding the stable operation area. The sharpening of the classification reduces the fine powder staying in the pulverizing portion, which causes the unstable behavior of the pulverizing roller, thereby enabling stable operation, which is shown in FIG.

On the other hand, since the coal which falls under the throat (this coal is usually discarded) is reduced by the drift suppression itself, in addition to the effect of the fallen coal itself, as a secondary effect, the primary air amount is reduced. This makes it possible to reduce the throat differential pressure and the resulting throat differential pressure. Reducing the primary air flow results in reduced fan power and improved mill exit fines particle size.

As described above, according to the embodiment of the present invention, the overall ripple effect is high.

[0053]

According to the present invention, since a plurality of partition members are provided on the outer peripheral portion of the crushing table, the upper surface of the air introduction throat group is disposed lower than the upper surface of the outer peripheral portion of the crushing table. Or, since a plurality of partition members are provided on the outer peripheral portion of the crushing table and the upper surface of the air introduction throat group is arranged lower than the upper surface of the outer peripheral portion of the crushing table, Since a gas or liquid nozzle is installed on the grinding table, and a scraper is installed on the grinding table, the pulverized coal is led out to the upper end of the throat without impairing the pulverized coal discharge efficiency from the grinding table, and pulverized at the upper part of the throat. It is possible to improve the method of merging the coal particles at the outlet with the primary air. As a result, the overall mill performance can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of a vertical roller mill according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a throat portion of the vertical roller mill according to the first embodiment and a plan view illustrating a configuration of an outer peripheral portion of a grinding table.

FIG. 3 is a sectional view taken along line AA in FIG. 2 (1).

FIG. 4 is a longitudinal sectional view showing a schematic configuration of a vertical roller mill according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of a throat portion of a vertical roller mill according to a second embodiment.

6 is a sectional view taken along line BB in FIG.

FIG. 7 is a longitudinal sectional view showing a schematic configuration of a fixed throat type vertical roller mill according to a conventional example.

FIG. 8 is a cross-sectional view illustrating a configuration of a throat portion of a vertical roller mill according to a conventional example.

9 is a sectional view taken along line CC in FIG.

FIG. 10 is a vertical cross-sectional view showing a configuration of a throat portion of a rotary throat type vertical roller mill according to a conventional example.

FIG. 11 is a sectional view taken along line DD in FIG. 10;

FIG. 12 is a plan view of a vertical roller mill according to third and fourth embodiments of the present invention.

FIG. 13 is a diagram illustrating an example of a drift suppression effect in the circumferential direction of the housing according to the present invention.

FIG. 14 shows the mixing and mixing of coal particles at the outlet of the pulverizing section according to the present invention.
It is a figure which shows the example of a dispersion degree improvement effect.

FIG. 15 is a diagram showing an example of the effect of classification sharpening according to the present invention.

FIG. 16 is a diagram showing an example of the effect of reducing the mill differential pressure and the grinding power according to the present invention.

FIG. 17 is a diagram showing an example in which stable operation is enabled by the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coal supply pipe 2 Pulverizing table 200 Partition member 201 Outer end 202 Pulverizing table upper surface 3 Pulverizing roller 4 Throat 41 Fixed throat 42 Rotating throat 400 Throat upper part 401 Throat upper surface 421 Throat port 422 Throat fin 5 Pulverizing part 6 Classifying part 61 First classification Part 62 Second classifier 7 Housing 10 Fixed classifier 11 Cone part 12, 21 Rotating blade 20 Rotary classifier 30 Coal pipe 101 Throat fin 102 Throat port 103 Crush table outer peripheral upper end 104 Throat upper end 108 Nozzle 109 Scraper

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazunori Sato 3-36 Takara-cho, Kure-shi, Hiroshima Prefecture Inside the Kure Research Laboratories Co., Ltd. (72) Inventor Yutaka Yutaka 3-36 Takara-cho, Kure-shi, Hiroshima Babcock-Hitachi Co., Ltd. (72) Hideo Mitsui, Inventor 6-9 Takaracho, Kure-shi, Hiroshima Babcock-Hitachi Kure Factory

Claims (6)

[Claims] 1. A pulverizing unit comprising: a pulverizing table and a pulverizing roller provided at a lower portion in a housing; and an air-introducing throat group disposed on an outer periphery of the pulverizing table. In a vertical roller mill set such that the velocity component of the air to be blown in the circumferential direction of the crushing table is opposite to the direction of the circumferential speed at the outer circumferential end of the crushing table, a plurality of partitions are provided on the outer circumferential portion of the crushing table. A vertical roller mill comprising members. 2. A pulverizing section comprising: a pulverizing table and a pulverizing roller provided at a lower portion in a housing; and an air-introducing throat group arranged on an outer periphery of the pulverizing table. In a vertical roller mill set such that the velocity component of the air to be blown in the circumferential direction of the grinding table is opposite to the direction of the circumferential speed at the outer circumferential end of the grinding table, the upper surface of the outer circumferential portion of the grinding table is A vertical roller mill, which is arranged to be higher than the upper surface of a throat group for introducing air. 3. The vertical roller mill according to claim 2, wherein a plurality of partition members are provided on an outer peripheral portion of the crushing table. 4. A pulverizing section comprising: a pulverizing table and a pulverizing roller provided at a lower portion in a housing; and an air-introducing throat group arranged on an outer periphery of the pulverizing table, and ejects from the air-introducing throat. In a vertical roller mill set such that the velocity component of the air to be blown in the circumferential direction of the crushing table is opposite to the direction of the circumferential speed at the outer peripheral end of the crushing table, the same as the circumferential speed direction of the crushing table. A vertical roller mill, wherein a gas nozzle or a liquid nozzle for injecting a gas or a liquid having a flow velocity direction is provided on an outer peripheral portion of the crushing table. 5. A pulverizing section comprising: a pulverizing table and a pulverizing roller provided at a lower portion in a housing; and an air-introducing throat group arranged on an outer periphery of the pulverizing table, and ejects from the air-introducing throat. In a vertical roller mill set such that the velocity component of the air to be blown in the circumferential direction of the crushing table is opposite to the direction of the circumferential speed at the outer peripheral end of the crushing table, the crushing on the inner peripheral side of the crushing roller is performed. A vertical roller mill wherein a plurality of partition members are radially disposed on a table with respect to a rotation axis of a crushing table. 6. The vertical roller mill according to claim 1, wherein a plurality of partition members are radially provided on the grinding table on the inner peripheral side of the grinding roller with respect to the rotation axis of the grinding table. Vertical roller mill.