JP7424117B2 - Vertical roller mill - Google Patents

Description

The present invention relates to a vertical roller mill.

Patent Document 1 listed below discloses a biomass pulverizer and a biomass/coal co-firing system that can efficiently discharge pulverized biomass powder to the outside. This background technology consists of a raw material supply pipe that supplies biomass raw materials from above in the vertical axis direction, a crushing table on which the biomass raw materials are placed, a drive unit that rotationally drives the crushing table, and a crusher that crushes the biomass raw materials by pressing force. It is equipped with a roller, a blowing means for air-flowing the pulverized biomass powder upward using an upward flow, and a classifier for classifying the biomass powder using an inner cylinder and an outer cylinder.

Japanese Patent Application Publication No. 2012-083016

By the way, in the above-mentioned background art, the biomass powder (pulverized material) that is not discharged to the outside from the classifier falls onto the crushing table through the gap between the raw material supply pipe and the outer cylinder. On the other hand, when pulverizing biomass raw materials, the supply flow rate is increased by reducing the diameter of the raw material supply pipe. In this case, since the influence of the upward flow on the gap increases, the crushed material cannot pass through the gap, and there is a possibility that the gap will eventually be closed.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to reduce the influence of upward flow more than before and to effectively supply pulverized material onto a pulverizing table.

In order to achieve the above object, in the present invention, as a first solving means related to a vertical roller mill, a vertical housing, a crushing part provided at a lower part of the vertical housing and crushing a material to be crushed,
a raw material supply section that supplies the material to be crushed to the crushing section from above; an airflow generating section that generates an upward flow that transports the crushed material generated in the crushing section upward; A method is adopted in which the present invention includes a classification section that classifies objects, and a guide section that is provided between the raw material supply section and the crushing section and guides the object to be crushed directly above the crushing section.

In the present invention, as a second solving means related to a vertical roller mill, in the first solving means, a means is adopted in which the lower end of the guide part contacts the object to be crushed loaded on the crushing part. do.

In the present invention, as a third solving means related to a vertical roller mill, a means is adopted in which the lower end portion has a shape having different heights in the vertical direction in the first or second solving means.

In the present invention, as a fourth solution related to a vertical roller mill, in the second solution, the shape has a part that contacts the object to be crushed and a part that does not contact the object to be crushed. Adopt.

In the present invention, as a fifth solving means related to a vertical roller mill, in any one of the second to fourth solving means, the lower end portion has a cylindrical shape provided concentrically with respect to the crushing portion. Adopt a method that says that there is.

In the present invention, as a sixth solving means related to a vertical roller mill, in any one of the first to fifth solving means, a roller mill is provided between the crushing section and the classifying section, and the crushed material is distributed. A method is adopted in which the device further includes a flow path adjustment section that changes the opening area of the flow opening.

In the present invention, as a seventh solution related to a vertical roller mill, a method is adopted in any of the first to sixth solutions, in which the material to be crushed is coal or biomass.

In the present invention, as an eighth solution related to a vertical roller mill, in any one of the first to seventh solutions, the lower end of the raw material supply section is provided above the lower end. , will be adopted.

According to the present invention, it is possible to effectively supply the pulverized material onto the pulverizing table while reducing the influence of upward flow compared to the conventional method.

1 is a longitudinal cross-sectional view showing the configuration of a vertical roller mill according to an embodiment of the present invention. It is a schematic diagram which expanded the guide lower end part in one Embodiment of this invention.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
The vertical roller mill A according to this embodiment uses coal or biomass as the material to be crushed. That is, this vertical roller mill A is a facility attached to a boiler of a thermal power plant, for example, and crushes the material to be crushed X, which is fuel for the boiler, to a predetermined particle size (optimum fuel particle size) and supplies it to the boiler. It constitutes a fuel supply system for

Here, the above-mentioned optimum fuel particle size differs between coal and biomass due to differences in their properties as fuels. The optimum fuel particle size for coal is, for example, several tens of micrometers, and the optimum fuel particle size for biomass is, for example, several hundred micrometers. Therefore, the performance of the vertical roller mill A is adjusted so that the particle size of the crushed material Xa discharged toward the boiler is changed depending on the coal or biomass.

A thermal power plant operates a boiler using either coal or biomass as fuel, and uses steam generated by the boiler to operate a turbine to drive a generator. That is, thermal power plants are operated while switching fuel to coal or biomass depending on the season. Therefore, the performance of the vertical roller mill A needs to be adjusted every time the externally supplied fuel is switched between coal and biomass.

As shown in FIG. 1, the vertical roller mill A according to this embodiment includes a vertical housing 1, a crushing section 2, a raw material supply section 3, an airflow generation section 4, a classification section 5, and a flow path adjustment section 6. We are prepared.

The vertical housing 1 is a bottomed cylindrical member in a vertical position. That is, this vertical housing 1 includes a housing body 1a, a support body 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 main body 1a is a substantially cylindrical member, and is supported in a vertical position by a support body 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 on the ground so that the housing body 1a is in a vertical position, that is, the center axis is in the vertical direction. The lid body 1c is a substantially disc-shaped member that closes the upper end of the vertical housing 1, and includes a discharge portion 1d. This discharge part 1d is an opening that discharges the crushed material Xa to the outside of the boiler or the like.

The crushing unit 2 includes a rotary table 2a, a plurality of crushing rollers 2b, a rotary power source 2c, and a coupling device 2d, and crushes coal or biomass, which is the object to be crushed, to produce a crushed product. The rotary table 2a is a rotating body that rotates in a horizontal position, and the upper surface thereof is an annular crushing surface 2e. The rotary table 2a rotates the crushing surface 2e within a horizontal plane by being rotationally driven by a rotary power source 2c via a coupling device 2d.

Note that the fracture surface 2e is an annular surface having a predetermined width when viewed from the vertical direction. Moreover, the inner side of the crushing surface 2e is provided with a central protrusion 2f that swells in a substantially conical shape when viewed from the horizontal direction, as shown in the figure. This central protrusion 2f is provided coaxially with the crushing surface 2e, and serves as a receiving portion for receiving the material to be crushed X falling from the raw material supply section 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. This crushing roller 2b is driven to rotate with the object to be crushed X sandwiched between it and the crushing surface 2e. The above-described object to be crushed X is crushed by being caught between the crushing surface 2e (upper surface) of the rotary table 2a and the circumferential surface of the crushing roller 2b, and becomes a crushed object Xa.

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

The rotary power source 2c is a prime mover provided with an output shaft in a horizontal position, and is connected to the rotary table 2a via a coupling device 2d. The coupler 2d is provided between the rotary power source 2c and the rotary table 2a, and is a speed reducer that decelerates the rotation of the rotary power source 2c and transmits the rotation to the rotary table 2a. That is, the coupler 2d also functions as a converter that decelerates the rotation of the rotary power source 2c and changes the center of rotation from the horizontal direction to the vertical direction.

The raw material supply section 3 is a tubular member supported in a vertical position by the lid 1c, and the material to be crushed X flows through the inside thereof. The central axis (vertical axis) of this raw material supply section 3 is coaxial with the rotation center of the rotary table 2a (crushing surface 2e). That is, the raw material supply section 3 supplies the material to be crushed X toward the center of the flow path adjustment section 6 from above. In addition, the lower end part of the raw material supply part 3 is provided above the guide lower end part 6d mentioned later, as shown in FIG.

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

Here, the pulverized material generated on the rotary table 2a is carried above the rotary table 2a by riding on the upward flow generated by the air flow generating section 4. Moreover, this pulverized material reaches the classification section 5 by passing through the flow path adjustment section 6 .

The classification section 5 is a rotary classifier that rotates around the raw material supply section 3, and its outer peripheral portion is an inlet for the pulverized material Xa, and its upper portion is an outlet for the pulverized material Xa. This classification section 5 selectively collects particles whose particle size is less than the optimum fuel particle size by wind pressure generated by rotation, and supplies the collected particles to the discharge section 1d, and removes particles whose particle size exceeds the optimum fuel particle size. drop it downwards.

The flow path adjustment section 6 is a plate-shaped member provided between the above-mentioned crushing section 2 and classification section 5, and includes a main body section 6a and a plurality of partial closing plates 6b. The flow path adjustment section 6 changes the opening area of the flow opening 6c by blocking a part of the flow opening 6c through which the crushed material Xa flows with a partial blocking plate 6b. Further, the flow path adjustment section 6 functions as a guide section that guides the material to be crushed X supplied from the upper raw material supply section 3 directly above the crushing section 2 .

The main body part 6a is a funnel-shaped (inverted cone-shaped) plate material in which one or more circulation openings are formed, and in addition to the plurality of circulation openings 6c, a cylindrical lower end part (guide lower end part 6d) and an upper fixing part. Equipped with 6e. This guide lower end 6d corresponds to the lower end of the present invention. Note that the plurality of flow openings 6c are substantially rectangular cutouts arranged at predetermined intervals in the circumferential direction.

The guide lower end portion 6d is a bottomless cylindrical portion provided vertically and concentrically with respect to the crushing section 2, and receives the material to be crushed Guide directly above. That is, the guide lower end 6d has an opening (lower discharge port 6f) formed at the lower end, and allows the material to be crushed X to fall from the lower discharge port 6f to a predetermined area including the center of the central protrusion 2f.

The lower guide end 6d is provided such that, for example, part or all of the lower discharge port 6f comes into contact with the object to be crushed X deposited on the central protrusion 2f. Further, as shown in FIG. 2, the cylindrical guide lower end portion 6d has a wave-like shape in which a portion that contacts the object to be crushed X and a portion that does not contact the object to be crushed are alternately repeated in the circumferential direction. That is, the lower guide end 6d has a shape having different heights in the vertical direction, and the lower discharge port 6f is not a simple circular opening, but is set in a shape that waves vertically with a predetermined amplitude.

The upper fixing part 6e is a circular opening having a diameter significantly larger than that of the lower guide end part 6d, and is fixed to the inner wall of the housing body 1a. That is, this upper fixing portion 6e is fixed to the inner wall of the housing body 1a without any gaps.

The plurality of partial blocking plates 6b are plate materials that are detachably attached to the main body portion 6a, and partially block each circulation opening 6c. More specifically, the partial closing plate 6b is attached to the main body 6a so as to partially close the area below the flow opening 6c. Such a partial closure plate 6b is attached to the main body 6a using a fastener such as a screw, for example, so that it can be easily attached to and removed from the main body 6a. Further, these partial blocking plates 6b are attached to the outer side of the main body part 6a formed in a funnel shape (inverted conical shape).

Here, since each partial blocking plate 6b closes the lower area of each circulation opening 6c, that is, the part closer to the raw material supply section 3, each circulation opening 6c with the partial blocking plate 6b attached is closed to the upper side, that is, the part of the housing body 1a. The area closer to the inner wall is open. This open portion is located, for example, directly below the inlet of the classification section 5.

Next, the operation of the vertical roller mill A according to this embodiment will be explained in detail.
First, a case where coal is used as the material to be crushed will be described. In this case, all of the plurality of partial blocking plates 6b in the flow path adjustment section 6 are removed, and the opening areas of all the flow openings 6c are set to be relatively large.

The removal work of the partial blocking plate 6b is performed by a worker entering the rotary table 2a while moving the crushing roller 2b in the crushing section 2 from a position facing the rotary table 2a. The work of removing the partial blocking plates 6b is easy because each partial blocking plate 6b is attached to the main body 6a with fasteners.

In this vertical roller mill A, the material to be crushed (coal) is sequentially and continuously supplied from the outside to the upper end of the raw material supply section 3 while the opening area of the flow opening 6c is set relatively wide. Then, the material to be crushed It is sequentially supplied to the surface 2e.

That is, the material to be crushed , and flows into the crushing surface 2e. Since such movement of the object X (coal) to be crushed occurs at various locations inside the crushing surface 2e, the object X (coal) to be crushed is sequentially supplied to various locations inside the crushing surface 2e.

Here, the material to be crushed X (coal) that has fallen from the raw material supply section 3 is guided by the guide lower end 6d of the flow path adjustment section 6 to just above the central protrusion 2f. The object to be crushed X (coal) falls from the lower discharge port 6f formed at the lower guide end 6d toward the center of the central protrusion 2f.

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

That is, as the crushing roller 2b rotates in accordance with the rotation of the crushing roller 2b, a pressing force against the crushing surface 2e is applied to the circumferential surface of the crushing roller 2b, so that the material to be crushed (coal) is crushed against the crushing surface 2e. It is crushed by the circumferential surface of the crushing roller 2b and crushed by the action of shearing force. By such a crushing action on the material to be crushed X (coal), crushed material Xa (pulverized coal) is gradually generated on the crushing surface 2e.

The crushed material Xa (pulverized coal) on the crushing surface 2e is blown upward by the upward flow generated around the outer periphery of the rotary table 2a by the airflow generating section 4. That is, among the crushed materials Xa (pulverized coal) on the crushing surface 2e, those having relatively small particle sizes float up due to the pressure of the upward flow. Then, this pulverized material Xa (pulverized coal) passes through the flow opening 6c of the flow path adjustment section 6 with an upward flow and reaches the classification section 5.

Here, the flow rate when the crushed material Xa (pulverized coal) passes through the flow opening 6c is relatively slow because the opening area of the flow opening 6c is set to be relatively large. That is, when the pulverized material Xa (pulverized coal) passes through each of the flow openings 6c of the flow path adjustment section 6, it rises without being substantially affected by the Bernoulli effect in fluid dynamics, that is, the effect of increasing the flow velocity.

In addition, the opening area of the circulation opening 6c in the case where the material to be crushed X is coal, that is, the opening area S1 of the circulation opening 6c in a state where the partial blocking plate 6b is removed from the main body part 6a, is the pulverized material Xa (pulverized coal). It is set as appropriate, taking into consideration the speed increasing effect that acts on the engine. That is, this opening area S1 is optimally set based on.

As a result, the pulverized material Xa (pulverized coal), which is relatively light due to its relatively small particle size, easily reaches the classification section 5 even if the speed is not increased through each of the flow openings 6c of the flow path adjustment section 6. Then, the pulverized material Xa (pulverized coal) whose particle size is less than or equal to the optimum fuel particle size is selectively collected in the classification section 5, and is discharged to the outside via the discharge section 1d.

On the other hand, the crushed material Xa (pulverized coal) not collected by the classification section 5 has a particle size larger than the optimum fuel particle diameter, and most of it falls onto the flow path adjustment section 6 below the classification section 5. do. This pulverized material Xa (pulverized coal) has a particle size larger than the optimum fuel particle size and needs to be further refined. Such pulverized material Xa (pulverized coal) flows down on the flow path adjustment section 6 . Then, this crushed material Xa (pulverized coal) is re-supplied onto the central protrusion 2f of the crushing section 2 together with the crushed material X (coal) falling from the raw material supply section 3 onto the flow path adjustment section 6.

In this way, the pulverized material Xa (pulverized coal) is resupplied onto the central protrusion 2f, but since the lower discharge port 6f is located directly above the central protrusion 2f, the upward flow generated by the air flow generating section 4 Not easily affected by That is, when the lower discharge port 6f is spaced apart from directly above the central protrusion 2f, the upward flow acts on the crushed material Xa (pulverized coal) and obstructs the falling of the crushed material Xa (pulverized coal); In this vertical roller mill A, since the lower discharge port 6f is located directly above the central protrusion 2f, the disturbance caused by upward flow is significantly reduced.

Further, in this vertical roller mill A, as shown in FIG. 2, the lower discharge port 6f is formed in a wave shape, and a portion of the lower guide end 6d is in contact with the material to be crushed X (coal). That is, the lower discharge port 6f is set in such a shape that a portion that contacts the object to be crushed X (coal) and a portion that does not contact the object to be crushed X (coal) alternately repeat. Therefore, the disturbance caused by the upward flow is further reduced.

On the other hand, when biomass is used as the material to be crushed X, all of the plurality of partial blocking plates 6b in the flow path adjustment section 6 are attached. That is, in this case, the opening area of all the flow openings 6c is set so that the object to be crushed X is relatively small. Note that the work for removing the partial blocking plates 6b is easy because each partial blocking plate 6b is attached to the main body portion 6a using fasteners.

In this vertical roller mill A, the material to be crushed (biomass) is sequentially and continuously supplied from the outside to the upper end of the raw material supply section 3 while the opening area of the flow opening 6c is set to be relatively small. That is, the material to be crushed X (biomass) that has fallen from the raw material supply section 3 is guided by the guide lower end 6d of the flow path adjustment section 6 to just above the central protrusion 2f.

Then, this material to be crushed X (biomass) falls toward the center of the central protrusion 2f from the lower discharge port 6f formed at the lower guide end 6d. Then, this material to be crushed It is sequentially supplied to the surface 2e.

Further, in parallel with the supply of the material to be crushed X (biomass) from the outside to the raw material supply section 3, the rotary table 2a is rotationally driven by the rotary power source 2c. As a result, the material to be crushed X (biomass) supplied to the crushing surface 2e is caught between the crushing surface 2e and the crushing roller 2b, and is crushed to become a crushed material Xa (fine biomass).

The crushed material Xa (fine biomass) generated on the crushing surface 2e is blown upward by an upward flow generated around the outer periphery of the rotary table 2a by the airflow generating section 4. That is, among the crushed materials Xa on the crushing surface 2e, those with relatively small particle sizes float up due to the pressure of the upward flow. Then, this pulverized material Xa (fine biomass) passes through the flow opening 6c of the flow path adjustment section 6 with an upward flow and reaches the classification section 5.

Here, the flow rate when the crushed material Xa (fine biomass) passes through the flow opening 6c is relatively fast because the opening area of the flow opening 6c is set to be relatively narrow. That is, when the pulverized material Xa (fine biomass) passes through each of the flow openings 6c of the flow path adjustment section 6, it rises due to the Bernoulli effect in fluid dynamics, that is, the effect of increasing the flow rate.

In addition, the opening area of the circulation opening 6c in the case where biomass is the material to be crushed It is set as appropriate, taking into consideration the speed increasing effect that acts on the engine. That is, this opening area S2 is optimally set based on experiments.

As a result, even if the pulverized material Xa (fine biomass) is relatively heavy due to its relatively large particle size, the speed is increased by each flow opening 6c of the flow path adjustment section 6, and the pulverized material Xa easily reaches the classification section 5. Then, the crushed material Xa (fine biomass) whose particle size is less than the optimum fuel particle size is selectively collected in the classification section 5, and is discharged to the outside via the discharge section 1d.

On the other hand, most of the crushed material Xa (fine biomass) not collected by the classification section 5 falls onto the flow path adjustment section 6 below the classification section 5. This pulverized material Xa (fine biomass) has a particle size larger than the optimum fuel particle size and needs to be further refined. Such pulverized material Xa (fine biomass) flows down on the flow path adjustment section 6, and together with the pulverized material X (coal) falling from the raw material supply section 3 onto the flow path adjustment section 6, the crushed material Xa (fine biomass) flows down the center of the pulverization section 2. It is resupplied onto the protrusion 2f.

In this way, the pulverized material Xa (fine biomass) is resupplied onto the central protrusion 2f, but since the lower discharge port 6f is located directly above the central protrusion 2f, the upward flow generated by the airflow generation unit 4 Not easily affected by Further, the lower discharge port 6f of the flow path adjustment section 6 is formed in a wave shape, and a portion of the guide lower end 6d is in contact with the material to be crushed X (coal). That is, the lower discharge port 6f is set in such a shape that a portion that contacts the object to be crushed X (coal) and a portion that does not contact the object to be crushed X (coal) alternately repeat. Therefore, in this vertical roller mill A, the disturbance caused by the upward flow is further reduced.

In addition, in this vertical roller mill A, the opening area of each circulation opening 6c through which the crushed material Xa flows is changed by attaching and detaching the partial closing plate 6b to the main body 6a, so the work required for the changeover is significantly reduced compared to the conventional one. Reduced. Therefore, according to the present embodiment, it is possible to significantly suppress a decrease in the operating rate of the vertical roller mill A due to switching of the material to be crushed X.

Note that the present invention is not limited to the above-described embodiment, and for example, the following modifications can be considered.
(1) In the above embodiment, the guide lower end 6d of the flow path adjustment section 6 has the shape shown in FIG. 2, but the present invention is not limited to this. For example, the shape of the lower discharge port 6f at the lower guide end 6d may be circular instead of waveform.

(2) In the above embodiment, the flow path adjustment section 6 is provided to change the opening area of the flow opening 6c by blocking a part of the flow opening 6c of the main body 6a with the partial blocking plate 6b. Not limited. For example, a flow path adjustment section in which the opening area of the flow opening 6c is fixed may be employed.

(3) In the above embodiment, coal and biomass are exemplified as the material to be crushed X, but the present invention is not limited thereto. The present invention can also be applied to materials to be crushed other than coal and biomass.

A Vertical roller mill 1 Vertical housing 1a Housing body 1b Support body 1c Lid 1d Discharge part 2 Grinding part 2a Rotary table 2b Grinding roller 2c Rotary power source 2d Coupler 2e Crushing surface 2f Central protrusion 3 Raw material supply part 4 Air flow generation Part 4a Air introduction part 4b Guide port 5 Classification part 6 Flow path adjustment part (guide part)
6a Main body 6b Partial blocking plate 6c Distribution opening 6d Lower guide end (lower end)
6e Upper fixing part 6f Lower discharge port

Claims (4)

Vertical housing,
a crushing section provided at the lower part of the vertical housing and crushing the object to be crushed;
a raw material supply unit that supplies the material to be crushed to the crushing unit;
an airflow generating section that generates an upward flow that transports the crushed material generated in the crushing section upward;
a classifying section that is provided above the crushing section and classifies the crushed material;
a guide section provided between the raw material supply section and the crushing section and guiding the object to be crushed supplied from the raw material supply section directly above the crushing section ;
The guide portion is vertical, and includes a wave-shaped lower end portion in which a portion that contacts the object to be crushed loaded on the crushing portion and a portion that does not contact the object to be crushed alternately repeat in the circumferential direction. Type roller mill. The vertical roller mill according to claim 1 , wherein the lower end portion has a cylindrical shape provided concentrically with respect to the crushing portion . The vertical roller mill according to claim 1 or 2 , further comprising a flow path adjustment section that is provided between the crushing section and the classification section and that switches the opening area of a distribution opening through which the crushed material flows. . The vertical roller mill according to any one of claims 1 to 3, wherein the material to be crushed is coal or biomass .

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