JP2021142453A - Vertical roller mill - Google Patents

Abstract

To supply crushed matter to a plurality of exhaust pipes more evenly than the prior art.SOLUTION: A vertical roller mill comprises: a vertical housing; a crushing part, provided at a lower part of the vertical housing, which crushes an object to be crushed; a raw material supply part that supplies the object to be crushed to the crushing part; an airflow generating part that generates upward flow for carrying crushed matter generated in the crushing part upward; a sorting part, provided above the crushing part, which sorts out the crushed matter; a swirl flow forming part that forms in the sorting part swirl flow of the crushed matter; and a plurality of exhaust pipes through which the crushed matter is collected from the swirl flow and exhausted to the outside.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vertical roller mill.

The following Patent Document 1 discloses a vertical roller mill. This vertical roller mill is provided with a housing, a crushing section, a transport mechanism, a classifier, a discharge pipe, a first condensing ring and a second condensing ring, and a first is provided between the crushing section and the classifier. By providing the condensing flow path formed by the condensing ring and the second condensing ring, it is possible to prevent the uncrushed material from passing through the classifier and being discharged to the outside from the discharge pipe.

JP-A-2019-000769

By the way, when a pulverized product (pulverized coal or biomass grains) is supplied from a vertical roller mill to a plurality of subsequent equipments (for example, a boiler), a plurality of the discharge pipes are provided. That is, in such a case, the number of discharge pipes is provided according to the number of subsequent equipment. The crushed material discharged from the classifier is distributed and supplied to each discharge pipe.

However, since the vertical roller mill does not have a function of evenly distributing the crushed material to each discharge pipe, there is a possibility that the amount of the crushed material supplied to each subsequent equipment may be uneven. For example, when the post-stage equipment is a burner, in the vertical roller mill, different amounts of crushed material are supplied to each burner as fuel, so that the calorific value is biased.

The present invention has been made in view of the above circumstances, and an object of the present invention is to supply a pulverized product to a plurality of discharge pipes more evenly than before.

In order to achieve the above object, in the present invention, as a first solution relating to a vertical roller mill, a vertical housing, a crushing portion provided under the vertical housing for crushing an object to be crushed, and the crushing portion are used. A raw material supply unit that supplies a material to be crushed to a unit, an airflow generation unit that generates an ascending flow that carries the crushed material generated in the crushed unit upward, and a unit that is provided above the crushed unit to classify the crushed material. A means is adopted in which a classification unit, a swirling flow forming unit for forming a swirling flow of the crushed material in the classification unit, and a plurality of discharge pipes for discharging the crushed material flowing in as the swirling flow to the outside are provided. ..

In the present invention, as a second solution for a vertical roller mill, in the first solution, the classifier is a rotary classifier that rotates in a horizontal plane, and the upward flow from the inflow portion on the outer periphery is described as described above. It is said that the swirling flow forming portion is an additional blade fixed to the rotary classifier, and one end of each of the plurality of discharge pipes opens above the rotary classifier at predetermined intervals. Adopt the means.

In the present invention, as a third solution for the vertical roller mill, in the second solution, the additional blade is provided outside the inflow portion.

In the present invention, as a fourth solution for the vertical roller mill, in the second solution, the additional blade is provided inside the inflow portion.

In the present invention, as a fifth solution for the vertical roller mill, in the second solution, the additional blade is provided on a support frame that supports the inflow portion.

According to the present invention, it is possible to supply the pulverized product to a plurality of discharge pipes more evenly than before.

It is a vertical sectional view which shows the structure of the vertical roller mill A which concerns on one Embodiment of this invention. It is a schematic diagram which shows the structure of the rotary classifier and 6 additional blades 7 in one Embodiment of this invention. It is a schematic diagram which shows the additional wing 7 in the modification of one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the vertical roller mill A according to the present embodiment uses coal or biomass as the object to be crushed X. That is, this vertical roller mill A is, for example, a facility attached to a boiler of a thermal power plant, and supplies the boiler by crushing the object to be crushed X, which is the fuel of the boiler, to a predetermined particle size (optimum fuel particle size). It constitutes the fuel supply system.

Here, the optimum fuel particle size differs between coal and biomass due to the difference in properties as a fuel. The optimum fuel particle size of coal is, for example, several tens of microns, and the optimum fuel particle size of biomass is, for example, several hundred microns. This vertical roller mill A crushes the object to be crushed X so that the particle size of the crushed material Xa discharged toward the boiler becomes the optimum fuel particle size.

As shown in FIG. 1, such a vertical roller mill A includes a vertical housing 1, a crushing section 2, a raw material supply section 3, an airflow generating section 4, a current reducing section 5, a classification section 6, a plurality of additional blades 7, and a plurality of additional blades 7. The discharge unit 8 is provided. Of these components, the plurality of additional blades 7 correspond to the swirling flow forming portion of the present invention.

The vertical housing 1 is a bottomed cylindrical member in a vertical posture. The vertical housing 1 includes a housing body 1a, a support 1b provided at the lower end of the housing body 1a, and a lid body 1c provided at the upper end of the housing body 1a.

The housing body 1a is a substantially cylindrical member, and is supported in a vertical posture by a support 1b. The support body 1b is a basic structure that closes the lower end of the housing body 1a and supports the housing body 1a with respect to the ground so that the housing body 1a is in a vertical posture, that is, the central axis is in the vertical direction. The lid body 1c is a substantially disk-shaped member in which the upper end of the vertical housing 1 is closed.

The crushing unit 2 includes a rotary table 2a, a plurality of crushing rollers 2b, a rotational power source 2c, and a connecting machine 2d, and crushes coal or biomass which is the object to be crushed X to generate a pulverized product. The rotary table 2a is a rotating body that rotates in a horizontal posture, and has a crushed surface 2e having an annular upper surface. The rotary table 2a is rotationally driven by the rotary power source 2c via the coupler 2d to rotate the crushed surface 2e in a horizontal plane.

The crushed surface 2e is an annular surface having a predetermined width when viewed from the vertical direction. Further, as shown in the figure, the inside of the crushed surface 2e is provided with a protruding portion 2f that rises in a substantially conical shape when viewed from the horizontal direction. The central protruding portion 2f is provided coaxially with the crushing surface 2e, and is a receiving portion that receives the object to be crushed X that falls from the raw material supply portion 3 above.

The crushing roller 2b is a circular roller whose peripheral surface faces the crushing surface 2e, and is rotatably supported by the vertical housing 1. The crushing roller 2b is driven to rotate with the object to be crushed X sandwiched between the crushing roller 2b and the crushing surface 2e. The above-mentioned object X to be crushed is crushed by being bitten between the crushed surface 2e (upper surface) of the rotary table 2a and the peripheral surface of the crushing roller 2b to become the crushed object Xa.

A plurality of such crushing rollers 2b are provided around the rotation center of the rotary table 2a (crushing surface 2e) at a predetermined angle when viewed from the vertical direction. For example, three crushing rollers 2b are provided around the center of rotation at an angle of 120 °. That is, the object to be crushed X is crushed at a plurality of discrete locations, for example, three locations on the rotary table 2a (crushed surface 2e) to become the crushed object Xa.

The rotary power source 2c is a prime mover provided so that the output shaft is in a horizontal posture, and is connected to the rotary table 2a via a coupling machine 2d. The coupler 2d is a speed reducer provided between the rotary power source 2c and the rotary table 2a, which slows down the rotation of the rotary power source 2c and transmits it to the rotary table 2a. That is, the coupler 2d also functions as a converter that slows down the rotation of the rotational power source 2c and converts the rotation axis from the horizontal direction to the vertical direction.

The raw material supply unit 3 is a tubular body rotatably supported by the lid body 1c, and extends directly above the crushing unit 2 in a vertical posture. In the raw material supply unit 3, the central axis (vertical axis) is coaxial with the rotation center of the rotary table 2a (crushing surface 2e), and the object to be crushed X circulates inside. That is, the raw material supply unit 3 supplies the object to be crushed X from directly above toward the center of the central protrusion 2f.

The airflow generation unit 4 includes an air introduction unit 4a and a plurality of guide ports 4b, receives compressed air F supplied from the outside, and forms an ascending flow in the vertical housing 1. The air introduction portion 4a is an inlet of the compressed air F, and is provided at the lower part of the vertical housing 1 as shown in the figure. The plurality of guide ports 4b are provided on the outer peripheral side of the rotary table 2a at predetermined intervals, and as shown by the arrows, the compressed air F flowing in from the air introduction portion 4a is discharged upward.

Here, the crushed material Xa generated on the rotary table 2a is conveyed above the rotary table 2a on the ascending current generated by the airflow generating unit 4. Further, the crushed product Xa reaches the rating unit 6 by passing through the contraction unit 5.

The condensing portion 5 is provided above the crushing portion 2 and below the classification portion 6, and includes a first condensing ring 5a and a second condensing ring 5b. The first condensing ring 5a is an annular body provided on the inner wall of the housing main body 1a, and projects inward (center side of the housing main body 1a) by a predetermined dimension from the inner wall. The first contraction ring 5a narrows the flow path of the crushed material Xa that is blown upward by the ascending current generated by the airflow generating unit 4.

The second condensing ring 5b is an annular body provided on the outer peripheral wall of the raw material supply unit 3, and projects outward (outer peripheral side of the housing body 1a) by a predetermined dimension from the outer peripheral wall. That is, the second condensing ring 5b narrows the flow path of the pulverized product Xa in the same manner as the first condensing ring 5a. Such a second condensing ring 5b and the above-mentioned first condensing ring 5a form a condensing passage having a predetermined width through which the pulverized product Xa passes.

The classification portion 6 is a cylindrical rotating body provided above the condensing portion 5 in the housing main body 1a and rotating around the raw material supply portion 3 (tubular body) extending in the vertical direction. That is, the classification unit 6 is a rotary classification machine. Such a rating unit 6 includes an inflow unit 6a and a support frame 6b.

The inflow portion 6a is composed of a plurality of slits formed in a substantially cylindrical outer peripheral portion in the classification portion 6. These slits are openings that are adjacent to each other and extend vertically. As shown in FIG. 2, such an inflow portion 6a is supported by the raw material supply portion 3 by the support frame 6b. The support frames 6b are provided around the raw material supply unit 3 at predetermined angular intervals to support the inflow unit 6a and allow the crushed product Xa to flow freely.

Such a classification unit 6 classifies the crushed material Xa that has entered the inside from the inflow portion 6a (outer peripheral portion) together with the ascending flow, based on the wind pressure generated by the rotation and the particle size (weight) of the crushed material Xa. That is, in the classification portion 6, among the crushed matter Xa that has entered the inside from the inflow portion 6a (outer peripheral portion), the crushed material Xa having a particle size equal to or smaller than the optimum fuel particle size (that is, the crushed material Xa having a relatively small diameter) is above (upper). Discharge from the outflow portion) to the upper side, that is, the discharge part 8, and discharge the crushed material Xa having a particle size exceeding the optimum fuel particle size from the lower part (lower outflow part) to the lower side, that is, the contraction part 5. do.

Further, such a classification unit 6 is rotationally driven by a drive unit (not shown). That is, a drive unit for the classification unit 6 is provided on the upper portion of the vertical housing 1, and the classification unit 6 is rotated around a vertical axis (rotational axis) via a raw material supply unit 3 (tubular body) in a vertical posture. Let me.

As shown in FIG. 2, the additional blades 7 are blades fixed to the classification unit 6 (rotary classifier), and a plurality of additional blades 7 are provided. Note that FIG. 2 is a schematic view of the classification portion 6 and the additional wing 7 viewed from above, that is, from the discharge portion 8 side, and shows the mounting position of the additional wing 7 with respect to the classification portion 6.

As shown in FIG. 2, the plurality of additional blades 7 are provided outside the inflow portion 5a and at predetermined intervals in the circumferential direction, and are flat plates of a predetermined size. The plurality of additional blades 7 rotate around the raw material supply unit 3 together with the classification unit 6 (rotary classifier), so that the raw material supply unit with respect to the pulverized material Xa taken into the inside of the classification unit 6 together with the ascending flow. 3 Apply a force to turn around.

For example, as shown in FIG. 2, eight additional blades 7 in the present embodiment are provided around the raw material supply unit 3 at an angular interval of 45 degrees. As shown in FIG. 2, the extending direction of the blade surface of each additional blade 7 is the same as the radial direction of the classification unit 6 (rotary classifier). As shown by the arrows, the plurality of additional blades 7 rotate around the raw material supply unit 3 at a predetermined speed to generate a swirling flow of the crushed material Xa inside the classification unit 6.

The discharge unit 8 is provided above the classification unit 6, and includes a discharge chamber 8a and a plurality of discharge pipes 8b. The discharge chamber 8a is a substantially annular space provided around the raw material supply unit 3, and the swirling flow of the crushed material Xa formed inside the classification unit 6 by the action of the plurality of additional blades 7 is downward (that is, that is). Enter from the upper part of the rating unit 6).

The plurality of discharge pipes 8b are provided at equal intervals on the upper plane (horizontal plane) of the discharge chamber 8a. For example, when the number of discharge pipes 8b is 4, one end of each of the four discharge pipes 8b opens around the raw material supply unit 3 at an angular interval of 90 °. When the number of discharge pipes 8b is 3, one end of each of the three discharge pipes 8b opens around the raw material supply unit 3 at an angular interval of 120 °. Such a plurality of discharge pipes 8b discharge the crushed material Xa flowing into one end as a swirling flow from the other end toward the outside (post-stage equipment).

Next, the operation of the vertical roller mill A according to the present embodiment will be described in detail.
In this vertical roller mill A, the object to be crushed X is sequentially and continuously supplied from the outside to the upper end of the raw material supply unit 3. Then, the object X to be crushed is sequentially supplied to the central protrusion 2f of the rotary table 2a via the raw material supply unit 3, and is sequentially supplied to the crushed surface 2e based on the shape effect of the central protrusion 2f.

That is, the object X to be crushed is supplied to the central protrusion 2f from above, but since the central protrusion 2f is shaped like a chevron with the center raised upward, along the inclined surface of the central protrusion 2f. It flows and flows from the inside into the crushed surface 2e. Since such movement of the object to be crushed X occurs at various places inside the crushed surface 2e, the object to be crushed X is sequentially supplied to the crushed surface 2e at various places inside.

On the other hand, the rotary table 2a is rotationally driven by the rotary power source 2c in parallel with the supply of the object X to be crushed from the outside to the raw material supply unit 3. As a result, the object X to be crushed supplied to the crushed surface 2e is bitten between the crushed surface 2e and the crushing roller 2b and crushed.

That is, as the crushing roller 2b rotates, the crushing roller 2b rotates drivenly and a pressing force acts on the peripheral surface of the crushing roller 2b against the crushing surface 2e. It is crushed with the peripheral surface of the surface and crushed by the action of shearing force. By such a crushing action on the object X to be crushed, the crushed material Xa is gradually generated on the crushed surface 2e.

Then, the crushed material Xa generated on the crushed surface 2e is blown upward by the ascending current generated on the outer periphery of the rotary table 2a by the airflow generating unit 4. That is, the crushed material Xa on the crushed surface 2e is blown upward by the action of the pressure of the ascending current. Then, the crushed product Xa passes through the condensing passage of the condensing portion 5 together with the ascending flow to reach the rating portion 6.

Here, when the crushed product Xa passes through the contraction passage, it receives the Bernoulli effect in fluid dynamics, that is, the effect of increasing the flow velocity (acceleration effect), and enters the inside from the inflow portion 6a provided on the outer periphery of the classification portion 6. .. Then, since the particles having a relatively large particle size in the pulverized product Xa are relatively heavy, they fall and are returned to the condensing portion 5. On the other hand, the particles having a relatively small particle size are supplied to the discharge unit 8 from the upper part of the classification unit 6.

Further, the crushed material Xa becomes a swirling flow due to the wind pressure generated by the additional blade 7, and enters the inside from the inflow portion 6a. That is, the crushed product Xa swirls around the raw material supply unit 3 inside the classification unit 6, but the particles having a relatively large particle size fall downward based on their own weight and are returned to the condensing unit 5, and the particle size is increased. Particles with a relatively small size rise in accordance with the ascending current and reach the discharge section 8.

The crushed material Xa that has entered from below as a swirling flow in the discharge unit 8 flows from below into one end of a plurality of discharge pipes 8b evenly arranged above while maintaining swirling in the substantially annular discharge chamber 8a. At this time, since the crushed material Xa swirls around the raw material supply unit 3 into the plurality of discharge pipes 8b which are opened at equal intervals in the horizontal plane, the crushed material Xa flows substantially evenly.

As described above, according to the vertical roller mill A, since the crushed material Xa flows into the discharge unit 8 as a swirling flow, it is possible to supply the crushed material Xa to the plurality of discharge pipes 8b more evenly than before. Therefore, according to the present embodiment, it is possible to more evenly supply the pulverized product Xa to the subsequent equipment.

Here, since the inflow portion 6a of the classification portion 6 is composed of a plurality of slits extending in the vertical direction, a turning force can be applied to the crushed product Xa as the classification portion 6 rotates. However, the inflow portion 6a of the classification unit 6 is not intended to swirl the crushed product Xa, and classifies the coarse powder having a relatively large diameter and the fine powder having a relatively small diameter by colliding with the crushed product Xa. It is a thing. Therefore, the inflow portion 6a cannot apply a turning force to the crushed material Xa.

With respect to such an inflow portion 6a, the plurality of additional blades 7 can exert a sufficient turning force on the crushed material Xa. For example, the plurality of additional blades 7 have a surface area sufficiently larger than that of the inflow portion 6a, and can give the crushed material Xa sufficient turning force necessary for making the crushed material Xa a swirling flow. ..

The present invention is not limited to the above embodiment, and for example, the following modifications can be considered.
(1) In the above embodiment, a plurality of additional blades 7 are adopted as the swirling flow forming portion for forming the swirling flow of the crushed material Xa in the classification portion 6, but the present invention is not limited to this. That is, the swirling flow forming portion of the present invention is not limited to the plurality of additional blades 7. For example, the crushed product Xa may be used as a swirling flow by injecting compressed gas (compressed air) into the rating unit 6.

(2) In the above embodiment, a plurality of additional blades 7 are provided on the outside of the inflow portion 5a, but the present invention is not limited to this. For example, as shown in FIG. 3A, a plurality of additional blades 7 may be provided inside the inflow portion 5a. In such a plurality of additional blades 7, the crushed material Xa can be used as a swirling flow around the raw material supply unit 3 as in the case of the additional blades 7 of the above embodiment.

(3) Further, as the mounting position of the plurality of additional blades 7, it is conceivable that the support frame 6b is used as shown in FIG. 3 (b). FIG. 3B shows a case where a plurality of additional blades 7 are provided on the upper support frame 6b of the classification unit 6, but if necessary, a plurality of additional wings 7 are provided on the lower support frame 6b of the classification unit 6. An additional wing 7 may be provided.

(4) In the above embodiment, coal and biomass are exemplified as the object to be crushed X, but the present invention is not limited thereto. The present invention can also be applied to a work piece X other than coal and biomass.

A, B Vertical roller mill X Crushed material Xa Crushed material 1 Vertical housing 1a Housing body 1b Support 1c Lid 2 Crushing part 2a Rotating table 2b Crushing roller 2c Rotating power source 2d Connecting machine 2e Crushing surface 2f Central protrusion 3 Raw material supply part 4 Air flow generation part 4a Air introduction part 4b Guide port 5 Constriction part 5a First condensing ring 5b Second condensing ring 6 Classification part 6a Inflow part 6b Support frame 7 Additional blade (swirl flow forming part)
8 Discharge section 8a Discharge chamber 8b Discharge pipe

Claims (5)

Vertical housing and
A crushing portion provided at the bottom of the vertical housing for crushing the object to be crushed, and a crushing portion.
A raw material supply unit that supplies the object to be crushed to the crushed unit,
An airflow generating part that generates an ascending flow that carries the crushed material generated in the crushing part upward,
A classifying section provided above the crushing section to classify the crushed product,
A swirling flow forming portion that forms a swirling flow of the crushed material in the classification portion, and a swirling flow forming portion.
A vertical roller mill including a plurality of discharge pipes for discharging the crushed material flowing in as a swirling flow to the outside. The classifying part is a rotary classifying machine that rotates in a horizontal plane, and takes in the crushed material together with the rising flow from the inflow part on the outer circumference.
The swirl flow forming portion is an additional blade fixed to the rotary classifier.
The vertical roller mill according to claim 1, wherein the plurality of discharge pipes have one end opened above the rotary classifier at predetermined intervals. The vertical roller mill according to claim 2, wherein the additional blade is provided outside the inflow portion. The vertical roller mill according to claim 2, wherein the additional blade is provided inside the inflow portion. The vertical roller mill according to claim 2, wherein the additional blade is provided on a support frame that supports the inflow portion.

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