JP7693365B2 - Classifier, power generation plant, and method for operating the classifier - Google Patents

Description

This disclosure relates to a classifier, a power generation plant, and a method for operating the classifier.

Conventionally, solid fuels (carbon-containing solid fuels) such as coal and biomass fuels are pulverized into fine powder within a specified particle size range by a pulverizer (mill) and then supplied to a combustion device. In the mill, solid fuels such as coal and biomass fuels fed to a pulverizing table are pinched between the pulverizing table and a pulverizing roller to pulverize them, and from the pulverized solid fuel (hereinafter, the pulverized solid fuel is referred to as "pulverized fuel"), fine fuels within a specified particle size range (fineness) are selected by a classifier, and transported to a boiler by a carrier gas (primary air) supplied from the outer periphery of the pulverizing table and combusted in a combustion device. In a thermal power plant, steam is generated by heat exchange with the combustion gas generated by burning the pulverized fuel in the boiler, and the steam is used to rotate and drive a steam turbine, which then rotates and drives a generator connected to the steam turbine to generate electricity.

As one of the classifiers provided in the mill, for example, a rotary classifier is known. The rotary classifier has a plurality of blades arranged at equal intervals in the circumferential direction around the rotation axis. The rotary classifier is a device that classifies pulverized fuel by, when the pulverized fuel passes between the plurality of blades rotating around the rotation axis, repelling coarse pulverized fuel (pulverized fuel larger than a predetermined particle size) that is heavily affected by weight and centrifugal force to the outer periphery of the blades, and allowing fine pulverized fuel (pulverized fuel smaller than a predetermined particle size) that is light in weight and is heavily affected by the conveying force of the primary air flow to pass to the inner periphery of the blades.
The rotary classifier also has a main body that rotates around a rotation axis. The main body holds the top and bottom of the blades, allowing the blades to revolve around the rotation axis. The main body is held by bearings and rotates at a predetermined rotation speed by a power source such as a motor. By changing this rotation speed, the force acting on the pulverized fuel can be adjusted to obtain a desired degree of fineness.

An example of a mill equipped with such a rotary classifier is the mill described in Patent Document 1.

JP 2021-30114 A

In recent years, mills have become larger. As mills become larger, rotary classifiers also become larger. In addition, the radial length (blade width) and vertical length (blade length) of the blades increase. As a result, the centrifugal force acting on the blades when the rotary classifier rotates also increases, causing the blades to bend more. If the blades bend too much, there is a problem that the blades will be permanently deformed and damaged. Furthermore, if the blades are deformed locally, the balance of the rotary classifier will be lost when it rotates. If the balance is lost, a large vibration load will be generated, which could lead to damage to bearings, etc.

In order to prevent deformation of the blades due to centrifugal force, in large mills, a reinforcing member that connects the blades together may be provided at approximately the center of the blades in the vertical direction. By providing the reinforcing member, even if the blades try to bend radially outward due to centrifugal force, the reinforcing member will pull the blades back radially inward because the blades are connected to each other in a ring shape via the reinforcing member. This reduces the bending of the blades due to centrifugal force.

However, conventional reinforcing members are provided between adjacent blades, and are provided so as to connect opposing plate surfaces. For this reason, when providing the reinforcing member, it is necessary to fix the reinforcing member in the narrow gap between the blades, which causes a problem that the work of fixing the reinforcing member and the blade (hereinafter referred to as the "fixing work") becomes cumbersome. Furthermore, because conventional reinforcing members are provided so as to connect opposing plate surfaces, the number of fixing points between the blade and the reinforcing member becomes twice the number of blades. This results in an increase in the number of fixing points. In particular, because a large number of blades are provided in a rotary classifier, the increase in the number of fixing points is remarkable. This results in a problem that the fixing work becomes cumbersome.

As described above, the fixing operation becomes complicated, which causes a problem that the process for manufacturing the rotary classifier becomes longer and the cost increases.
In addition, the blades wear out over a long period of use. When the blades wear out, they need to be replaced, but when replacing the blades, the fixing work is also required. This makes the fixing work complicated, which lengthens the process when replacing the blades, and increases costs.

The present disclosure has been made in consideration of these circumstances, and aims to provide a classifier, a power generation plant, and a method for operating a classifier that can simplify the work of fixing the reinforcing member and the blade.

In order to solve the above problems, the classifier, power generation plant, and classifier operating method of the present disclosure employ the following measures.
A classifier according to one aspect of the present disclosure is a classifier that rotates about a central axis extending in an up-down direction, classifies particles introduced from the radial outside by a carrier gas, and introduces the particles having a predetermined particle size or less into its interior, and is equipped with a main body that rotates about the central axis, a plurality of plate-shaped blades that extend in an up-down direction and have their upper and lower parts fixed to the main body, and a reinforcing member that reinforces the plurality of blades, wherein the plurality of blades are arranged in a line at a predetermined interval in the circumferential direction, at a position spaced a predetermined distance outward in the radial direction from the central axis, so that the plate surfaces of the blades adjacent in the circumferential direction face each other, and the reinforcing member is fixed to the radial inner ends of the blades and connects the blades that are arranged in the circumferential direction to each other.

In addition, a method of operating a classifier according to one aspect of the present disclosure is a method of operating a classifier that rotates around a central axis extending in the vertical direction, classifies particles introduced from the radial outside by a carrier gas, and introduces the particles having a predetermined particle size or less into the inside, the classifier includes a main body that rotates around the central axis, a plurality of plate-shaped blades that extend in the vertical direction and have their upper and lower parts fixed to the main body, and a reinforcing member that reinforces the plurality of blades, the plurality of blades are arranged side by side at a predetermined interval in the circumferential direction at a position spaced a predetermined distance outward in the radial direction from the central axis so that the plate surfaces of the blades adjacent in the circumferential direction face each other, the reinforcing member is fixed to the inner end of the blade in the radial direction and connects the blades arranged in the circumferential direction, and includes a step of classifying the particles into particles larger than a predetermined particle size and particles having a predetermined particle size or less by the blades.

This disclosure simplifies the process of fixing the reinforcing member and the blade.

FIG. 2 is a configuration diagram showing a solid fuel pulverizer and a boiler according to the first embodiment of the present disclosure. FIG. 1 is a vertical cross-sectional view showing a rotary classifier according to a first embodiment of the present disclosure. 1 is a horizontal cross-sectional view showing a rotary classifier according to a first embodiment of the present disclosure. FIG. 4 is an enlarged view of a portion IV in FIG. 3 . FIG. 4 is a horizontal cross-sectional view showing a rotary classifier according to a second embodiment of the present disclosure. FIG. 6 is an enlarged view of a portion VI in FIG. 5 . FIG. 13 is a diagram showing a reinforcing member according to a modified example of the second embodiment of the present disclosure, as viewed from the inside space. FIG. 11 is a horizontal cross-sectional view showing a rotary classifier according to a third embodiment of the present disclosure. FIG. 9 is an enlarged view of a portion IX of FIG. 8 . FIG. 2 is a horizontal cross-sectional view showing a rotary classifier according to a comparative example of the present disclosure.

First Embodiment
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present disclosure will now be described with reference to the drawings. A power plant 1 according to this embodiment includes a solid fuel pulverizer 100 and a boiler 200.
In the following explanation, "upper" refers to the vertically upper direction, and "upper" in terms such as upper part and upper surface refers to the vertically upper part. Similarly, "lower" refers to the vertically lower part, and the vertical direction is not precise and may include errors.

The solid fuel pulverization device 100 of this embodiment is a device that pulverizes solid fuel (carbon-containing solid fuel) such as coal or biomass fuel, generates pulverized fuel, and supplies it to a burner (combustion device) 220 of a boiler 200.
The power plant 1 including the solid fuel pulverizer 100 and the boiler 200 shown in FIG. 1 is equipped with one solid fuel pulverizer 100, but it may also be a system equipped with multiple solid fuel pulverizers 100 corresponding to each of the multiple burners 220 of one boiler 200.

The solid fuel pulverizer 100 of this embodiment includes a mill (pulverizer) 10, a coal feeder (fuel supplier) 20, a blower (carrier gas supplier) 30, a state detector 40, and a controller (determiner) 50.

The mill 10, which pulverizes solid fuel such as coal or biomass fuel to be supplied to the boiler 200 into fine fuel, which is a finely powdered solid fuel, may be of a type that pulverizes only coal, may be of a type that pulverizes only biomass fuel, or may be of a type that pulverizes biomass fuel together with coal.
Here, biomass fuels are organic resources derived from renewable living organisms, such as thinned wood, waste wood, driftwood, grass, waste, sludge, tires, and recycled fuels (pellets and chips) made from these materials, but are not limited to the ones presented here.Biomass fuels are carbon neutral, meaning they do not emit carbon dioxide, a greenhouse gas, because they capture carbon dioxide during the biomass growth process, and various uses of biomass fuels are being considered.

The mill 10 includes a housing 11, a grinding table 12, grinding rollers 13, a drive unit 14, a mill motor 15 connected to the drive unit 14 to rotate the grinding table 12, a rotary classifier 16, a fuel supply unit 17, and a classifier motor 18 to rotate the rotary classifier 16. The rotary classifier 16 may be installed separately from the mill 10.
The housing 11 is formed in a cylindrical shape extending in the vertical direction, and is a case that accommodates the grinding table 12, the grinding rollers 13, the rotary classifier 16, and the fuel supply unit 17.
A fuel supply unit 17 is attached to the center of the ceiling portion 42 of the housing 11. This fuel supply unit 17 supplies solid fuel guided from the bunker 21 into the housing 11, and is disposed in the vertical direction at the center position of the housing 11 with its lower end extending into the interior of the housing 11.

A drive unit 14 is provided near the bottom surface 41 of the housing 11, and the grinding table 12 is rotatably disposed and rotated by the driving force transmitted from a mill motor 15 connected to the drive unit 14.
The grinding table 12 is a circular member in a plan view, and is disposed so as to face the lower end of the fuel supply unit 17. The upper surface of the grinding table 12 may have an inclined shape, for example, low at the center and high toward the outside, and the outer periphery may have a shape that is curved upward. The fuel supply unit 17 supplies solid fuel (for example, coal or biomass fuel in this embodiment) from above toward the grinding table 12 below, and the grinding table 12 grinds the supplied solid fuel between the grinding roller 13.

When solid fuel is fed from the fuel supply unit 17 toward the approximate center region of the grinding table 12, the centrifugal force generated by the rotation of the grinding table 12 guides the solid fuel to the outer periphery of the grinding table 12, where it is pinched and ground between the grinding table 12 and the grinding rollers 13. The ground solid fuel is blown upward by the carrier gas (hereinafter referred to as primary air) guided from the carrier gas flow path (hereinafter referred to as primary air flow path) 100a, and is guided to the rotary classifier 16.
An outlet (not shown) is provided on the outer periphery of the grinding table 12, through which the primary air flowing in from the primary air passage 100a flows out into the space above the grinding table 12 in the housing 11. A swirling blade (not shown) is provided at the outlet, which applies a swirling force to the primary air blown out from the outlet. The primary air given a swirling force by the swirling blade becomes an airflow having a swirling velocity component, and conveys the solid fuel pulverized on the grinding table 12 to the rotary classifier 16 located at the upper part in the housing 11. Among the pulverized solid fuel, particles larger than a predetermined particle size are classified by the rotary classifier 16, or fall without reaching the rotary classifier 16, are returned to the grinding table 12, and are pulverized again between the grinding table 12 and the grinding roller 13.

The crushing roller 13 is a rotating body that crushes the solid fuel supplied onto the crushing table 12 from the fuel supply unit 17. The crushing roller 13 is pressed against the upper surface of the crushing table 12 and cooperates with the crushing table 12 to crush the solid fuel.
1 shows only one representative crushing roller 13, but multiple crushing rollers 13 are arranged at regular intervals in the circumferential direction so as to press against the upper surface of the crushing table 12. For example, three crushing rollers 13 are arranged at equal intervals in the circumferential direction on the outer periphery at angular intervals of 120°. In this case, the portions where the three crushing rollers 13 come into contact with the upper surface of the crushing table 12 (pressing portions) are equidistant from the central axis of rotation of the crushing table 12.

The crushing roller 13 can be swung and displaced up and down by the journal head 45, and is supported so as to be able to move toward and away from the upper surface of the crushing table 12. When the crushing table 12 rotates, the crushing roller 13 receives a rotational force from the crushing table 12 and rotates with it, with the outer circumferential surface of the crushing roller 13 in contact with the solid fuel on the upper surface of the crushing table 12. When solid fuel is supplied from the fuel supply unit 17, the solid fuel is pressed between the crushing roller 13 and the crushing table 12 and crushed.

The support arm 47 of the journal head 45 is supported on the side of the housing 11 by a support shaft 48 whose middle part is aligned horizontally, allowing the crushing roller 13 to swing and displace in the vertical direction around the support shaft 48. A pressing device 49 is provided on the upper end part on the vertically upper side of the support arm 47. The pressing device 49 is fixed to the housing 11, and applies a load to the crushing roller 13 via the support arm 47 etc. so as to press the crushing roller 13 against the crushing table 12.

The drive unit 14 is a device that transmits a driving force to the grinding table 12 and rotates the grinding table 12 around its central axis. The drive unit 14 is connected to the mill motor 15 and transmits the driving force of the mill motor 15 to the grinding table 12.

The rotary classifier 16 is provided at the top of the housing 11 and has a hollow, generally inverted cone-shaped exterior. The rotary classifier 16 is provided with a plurality of blades 60 extending in the vertical direction at its outer periphery. The blades 60 are provided at predetermined intervals (equally spaced) around the central axis C of the rotary classifier 16.
The rotary classifier 16 is a device that classifies the solid fuel pulverized by the pulverizing table 12 and the pulverizing roller 13 (hereinafter, the pulverized solid fuel is referred to as "pulverized fuel") into fuel having a particle diameter larger than a predetermined particle diameter (for example, 70 to 100 μm for coal) (hereinafter, the pulverized fuel having a particle diameter larger than the predetermined particle diameter is referred to as "coarse pulverized fuel") and fuel having a particle diameter smaller than the predetermined particle diameter (hereinafter, the pulverized fuel having a particle diameter smaller than the predetermined particle diameter is referred to as "fine pulverized fuel"). The rotary classifier 16 that classifies by rotation is also called a rotary separator, and is given a rotational driving force by a classifier motor 18 controlled by a control unit 50, and rotates around the fuel supply unit 17 centering on a cylindrical shaft 71 (see FIG. 2) that extends in the vertical direction of the housing 11. Details of the rotary classifier 16 will be described later.
The classifier may be a fixed classifier having a fixed hollow inverted cone-shaped casing and a plurality of fixed swirling vanes, instead of the blades 60, on the outer periphery of the casing.

When the pulverized fuel reaches the rotary classifier 16, due to the relative balance between the centrifugal force generated by the rotation of the blades 60 and the centripetal force of the primary air flow, the large diameter coarse pulverized fuel is knocked down by the blades 60 and returned to the grinding table 12 where it is pulverized again, and the fine pulverized fuel is led to the outlet port 19 in the ceiling 42 of the housing 11. The fine pulverized fuel classified by the rotary classifier 16 is discharged from the outlet port 19 together with the primary air into the fine fuel supply passage 100b and supplied to the burner 220 of the boiler 200. When the solid fuel is coal, the fine fuel supply passage 100b is also called a pulverized coal pipe.

The fuel supply unit 17 is attached with its lower end extending vertically into the interior of the housing 11 so as to penetrate the ceiling portion 42 of the housing 11, and supplies solid fuel input from the upper portion of the fuel supply unit 17 to an approximately central region of the grinding table 12. The fuel supply unit 17 is supplied with solid fuel from the coal feeder 20.
The upper part of the fuel supply unit 17 has a horizontal cross section that changes from rectangular to circular in order to connect the rectangular outlet of the coal feeder 20 to the cylindrical lower part of the fuel supply unit 17 .

The coal feeder 20 includes a transport unit 22 and a coal feeder motor 23. The transport unit 22 is, for example, a belt conveyor, and transports the solid fuel discharged from the lower end of a downspout 24 located directly below the bunker 21 to the top of the fuel supply unit 17 of the mill 10 by the driving force provided by the coal feeder motor 23, and inputs the solid fuel into the fuel supply unit 17.
Normally, primary air is supplied to the inside of the mill 10 to transport pulverized fuel to the burner 220, and the pressure therein is higher than that of the coal feeder 20 and the bunker 21. The downspout 24, which is a pipe extending in the vertical direction directly below the bunker 21, holds fuel in a layered state inside, and the solid fuel layers layered inside the downspout 24 ensure a sealing performance that prevents the primary air and pulverized fuel on the mill 10 side from flowing back to the bunker 21 side.
The amount of solid fuel supplied to the mill 10 is adjusted, for example, by the moving speed of the belt conveyor of the transport unit 22.

The blower section 30 is a device that blows primary air into the housing 11 to dry the pulverized fuel and to transport the fuel to the rotary classifier 16 .
In order to appropriately adjust the flow rate and temperature of the primary air blown into the inside of the housing 11, in this embodiment, the blower section 30 is equipped with a primary air fan (PAF) 31, a hot gas flow path 30a, a cold gas flow path 30b, a hot gas damper 30c, and a cold gas damper 30d.

In this embodiment, the hot gas flow path 30a supplies a portion of the air (outside air) sent out from the primary air ventilator 31 as hot gas that has been heated by passing through a heat exchanger 34, such as an air preheater. A hot gas damper 30c is provided downstream of the hot gas flow path 30a. The opening degree of the hot gas damper 30c is controlled by the control unit 50. The flow rate of the hot gas supplied from the hot gas flow path 30a is determined by the opening degree of the hot gas damper 30c.

The cold gas flow path 30b supplies a portion of the air sent out from the primary air ventilator 31 as cold gas at room temperature. A cold gas damper 30d is provided downstream of the cold gas flow path 30b. The opening degree of the cold gas damper 30d is controlled by the control unit 50. The flow rate of the cold gas supplied from the cold gas flow path 30b is determined by the opening degree of the cold gas damper 30d.

In this embodiment, the flow rate of the primary air is the sum of the flow rate of the hot gas supplied from the hot gas flow path 30a and the flow rate of the cold gas supplied from the cold gas flow path 30b, and the temperature of the primary air is determined by the mixing ratio of the hot gas supplied from the hot gas flow path 30a and the cold gas supplied from the cold gas flow path 30b, and is controlled by the control unit 50.
In addition, the oxygen concentration of the primary air blown from the primary air passage 100a to the inside of the housing 11 may be adjusted by introducing a portion of the combustion gas discharged from the boiler 200 via a gas recirculation fan (not shown) into the hot gas supplied from the hot gas passage 30a and mixing it.

In this embodiment, the state detection unit 40 of the mill 10 transmits measured or detected data to the control unit 50. The state detection unit 40 of this embodiment is, for example, a differential pressure measurement means, and measures the differential pressure between the pressure at the portion where the primary air flows into the inside of the housing 11 from the primary air flow passage 100a and the pressure at the outlet port 19 where the primary air and the pulverized fuel are discharged from the inside of the housing 11 to the pulverized fuel supply flow passage 100b as the differential pressure of the mill 10. An increase or decrease in this differential pressure of the mill 10 corresponds to an increase or decrease in the amount of pulverized fuel circulating between the vicinity of the rotary classifier 16 inside the housing 11 and the vicinity of the grinding table 12 due to the classification effect of the rotary classifier 16. In other words, by adjusting the rotation speed of the rotary classifier 16 in accordance with the pressure difference of the mill 10, the amount of pulverized fuel discharged from the outlet port 19 can be adjusted in relation to the amount of solid fuel supplied to the mill 10.Therefore, within the range in which the particle size of the pulverized fuel does not affect the combustibility of the burner 220, an amount of pulverized fuel corresponding to the amount of solid fuel supplied to the mill 10 can be stably supplied to the burner 220 provided in the boiler 200.
The state detection unit 40 in this embodiment is, for example, a temperature measuring means, which detects the temperature of the primary air supplied to the inside of the housing 11 (the temperature of the primary air at the mill inlet) and the temperature of the primary air from the space above the grinding table 12 inside the housing 11 to the outlet port 19, and controls the blower unit 30 so that the temperature does not exceed the upper limit temperature. The upper limit temperature is determined taking into consideration the possibility of ignition of the solid fuel, etc. The primary air is cooled inside the housing 11 by transporting the pulverized fuel while drying it, and the temperature of the primary air at the outlet port 19 is, for example, about 60 to 90 degrees.

The control unit 50 is a device that controls each part of the solid fuel pulverization device 100 .
The control unit 50 may, for example, transmit a drive command to the mill motor 15 to control the rotation speed of the grinding table 12 .
The control unit 50, for example, transmits a drive command to the classifier motor 18 to control the rotational speed of the rotary classifier 16 to adjust the classification performance, and optimizes the differential pressure of the mill 10, i.e., the circulation amount of pulverized fuel inside the mill 10, within a predetermined range, thereby enabling a stable supply of pulverized fuel to the burner 220.
In addition, the control unit 50 can adjust the amount of solid fuel supplied (coal supply amount) that the conveying unit 22 conveys and supplies to the fuel supply unit 17 by, for example, transmitting a drive instruction to the coal supply motor 23 of the coal supply unit 20.
Furthermore, the control unit 50 can adjust the flow rate and temperature of the primary air by controlling the opening of the hot gas damper 30c and the cold gas damper 30d by transmitting an opening instruction to the blower unit 30. Specifically, the control unit 50 controls the opening of the hot gas damper 30c and the cold gas damper 30d so that the flow rate of the primary air supplied to the inside of the housing 11 and the temperature of the primary air at the outlet port 19 become predetermined values set in accordance with the amount of coal feed for each type of solid fuel.

The control unit 50 is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium in the form of a program, for example, and the CPU reads this program into the RAM and executes information processing and arithmetic processing to realize various functions. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories. The HDD may also be replaced with a solid-state disk (SSD), etc.

Next, we will explain the boiler 200, which generates steam by burning the pulverized fuel supplied from the solid fuel pulverizer 100. The boiler 200 is equipped with a furnace 210 and a burner 220.

The burner 220 is a device that burns pulverized fuel to form a flame using primary air containing pulverized fuel supplied from the pulverized fuel supply passage 100b and secondary air supplied by heating air (outside air) sent out from a forced draft fan (FDF: Forced Draft Fan) 32 in a heat exchanger 34. The pulverized fuel is burned in the furnace 210, and the high-temperature combustion gas is exhausted to the outside of the boiler 200 after passing through heat exchangers (not shown) such as an evaporator, a superheater, and a coal economizer.

The combustion gas discharged from the boiler 200 undergoes a predetermined treatment in an environmental device (such as a denitration device or an electric dust collector, not shown), and then undergoes heat exchange between the air discharged from the primary air fan 31 and the air discharged from the forced draft fan 32 in a heat exchanger 34, such as an air preheater, and is then guided to a chimney (not shown) via an induced draft fan (IDF) 33 and released into the outside air. The air discharged from the primary air fan 31, heated by the combustion gas in the heat exchanger 34, is supplied to the above-mentioned hot gas flow path 30a.
The water supplied to each heat exchanger of boiler 200 is heated in a coal economizer (not shown), and then further heated by an evaporator (not shown) and a superheater (not shown) to generate high-temperature, high-pressure steam. This is then sent to the steam turbine (not shown), which is the power generation section, to rotate the steam turbine, which in turn rotates a generator (not shown) connected to the steam turbine to generate electricity, thereby constituting power generation plant 1.

Next, the details of the rotary classifier 16 will be described. In the following description, "circumferential direction" and "radial direction" refer to the "circumferential direction" and "radial direction" when centered on the central axis C.

The rotary classifier 16 is provided on the upper part of the housing 11 as shown in FIG. 1. As shown in FIG. 2, the rotary classifier 16 rotates around a central axis C extending in the vertical direction. In this embodiment, the rotary classifier 16 rotates clockwise in a plan view as shown by the arrow A1 in FIG. 2 and FIG. 3. The rotation direction of the rotary classifier 16 is opposite to the swirling direction of the primary air formed by the swirling blades installed at the air outlet. The rotary classifier 16 is given a rotational driving force by a motor (not shown). The rotation speed of the motor is controlled by the control unit 50.

As shown in Figures 2 and 3, the rotary classifier 16 includes a main body 70 having a hollow, generally inverted cone-shaped exterior, a number of blades 60 provided on the outer periphery of the main body 70, and a reinforcing member 80 that reinforces the blades 60.

The main body 70 rotates around the central axis C. The main body 70 has a space (internal space S1) formed therein. The main body 70 integrally has a cylindrical shaft 71 that covers the fuel supply unit 17 and extends along the central axis C, an upper end 72 that extends radially from the upper end of the cylindrical shaft 71, and a lower end 73 that extends radially from the lower end of the cylindrical shaft 71. The upper end 72 defines the upper end of the internal space S1. The lower end 73 defines the lower end of the internal space S1. The upper end 72 has an opening 72a to which the outlet port 19 (see FIG. 1) is connected.

Each blade 60 extends in the vertical direction. Each blade 60 is a flat plate-shaped member. The upper end of each blade 60 is fixed to the upper end 72. The lower end of each blade 60 is fixed to the lower end 73. Each blade 60 is inclined so that the lower end is closer to the central axis C than the upper end. An opening 72a is formed in the upper end 72.

As shown in FIG. 3, the blades 60 are arranged at a predetermined distance from the central axis C of the rotary classifier 16 in the radial direction. The blades 60 are arranged in parallel at a predetermined interval (equal interval) in the circumferential direction around the central axis C. In addition, each blade 60 is arranged so as to be inclined at a predetermined angle with respect to the radial direction when viewed in a plan view. A gap is formed between adjacent blades 60 in the circumferential direction. The gap communicates with an internal space S1, which is the space inside the blades 60 in the radial direction, and an external space S2, which is the space outside the blades 60 in the radial direction. Pulverized fuel is introduced to each blade 60 together with primary air flowing from the outside to the inside in the radial direction.

Each blade 60 has an impact surface 61 which is the front surface in the direction of rotation, a back surface 65 which is the rear surface in the direction of rotation, and two side surfaces 68 which connect the impact surface 61 and the back surface 65.
As shown in Fig. 3, the pulverized fuel including the pulverized fuel B2 and the coarse pulverized fuel B1 collides with the collision surface 61. The pulverized fuel that collides with the collision surface 61 is subjected to a radial outward force indicated by an arrow A4 (a force toward the external space S2 due to centrifugal force or the like) and a radial inward force indicated by an arrow A5 (a force toward the internal space S1 due to the flow of primary air). Since the coarse pulverized fuel B1 is heavy, a strong outward force is applied to the coarse pulverized fuel B1 that collides with the collision surface 61 due to the influence of the centrifugal force. As a result, the coarse pulverized fuel B1 is repelled toward the outside of the blade 60 (the external space S2 side) against the inward force, as indicated by an arrow A2. On the other hand, since the pulverized fuel B2 is light in weight, a strong inward force is applied to the pulverized fuel B1 due to the flow of primary air. As a result, the force acting on the pulverized fuel B2 is predominantly an inward force, so that the pulverized fuel B2 is repelled toward the inside of the blades 60 (toward the internal space S1) as shown by the arrow A3.
Based on this principle, the rotary classifier 16 classifies the coarse pulverized fuel B1 and the fine pulverized fuel B2.

The reinforcing member 80 is an annular member as shown in Fig. 3. As shown in Fig. 2, the reinforcing member 80 has a substantially circular cross section in the circumferential direction (cross section taken along a plane perpendicular to the circumferential direction).

The outer peripheral surface of the reinforcing member 80 is fixed to all of the blades 60 arranged in a line in the circumferential direction. In detail, the outer peripheral surface of the reinforcing member 80 is fixed to the radial inner end of each blade 60. The reinforcing member 80 connects all of the blades 60 arranged in a line in the circumferential direction.

The reinforcing member 80 and the blade 60 are connected by a welded portion W1, as shown in FIG. 4. In other words, the reinforcing member 80 and the blade 60 are fixed by welding. The welded portion W1 is provided on the radially inner side surface 68 and part of the back surface 65 of the blade 60. The welded portion W1 is not provided on the impact surface 61.

As shown in FIG. 2, the reinforcing member 80 is located between the upper end 72 and the lower end 73 that support and secure the blade 60, and more specifically, is fixed approximately in the center in the vertical direction.

When the rotary classifier 16 rotates, centrifugal force acts on each blade 60 (see arrows F1 and F2 in FIG. 2). As described above, the upper and lower ends of each blade 60 are fixed to the main body 70. Therefore, a force acts on the vertical center of each blade 60 to bend radially outward. At this time, because each blade 60 is connected by the reinforcing member 80, a force pulling the blades 60 radially inward is applied by the reinforcing member 80. This makes it possible to suppress bending (deformation) of the blades 60 radially outward.

According to this embodiment, the following advantageous effects are obtained.
In this embodiment, the reinforcing member 80 is fixed to the inner end of the blade 60. Therefore, the number of welding points of the reinforcing member 80 to one blade 60 can be reduced to one. This makes it possible to reduce the number of welding points between the blade 60 and the reinforcing member 80 compared to a case where multiple welding points are provided between one blade 60 and the reinforcing member 80. Therefore, the work of fixing the blade 60 and the reinforcing member 80 can be simplified. Furthermore, the process of manufacturing the rotary classifier 16 can be shortened, and the work cost can be reduced.
An example of a case where a single blade 60 is provided with a plurality of welded points to the reinforcing member 80 is a case where a plurality of reinforcing members 80' are provided between adjacent blades 60 and welded to connect the plate surfaces of the opposing blades 60, as shown in Fig. 10 as a comparative example. In this example, the reinforcing members 80' are welded to both plate surfaces of each blade 60. That is, each blade 60 has two welded points.

In addition, the blade 60 will wear out over a long period of use. When the blade 60 wears out, it will need to be replaced, but when replacing the blade 60, the blade 60 and the reinforcing member 80 will also need to be fixed together. Therefore, by simplifying the fixing process, the process can be shortened and the work costs can be reduced when replacing the blade 60.

In addition, the number of welding points between the blade 60 and the reinforcing member 80 can be reduced, and therefore the number of materials (e.g., materials used for welding) used to fasten the blade 60 and the reinforcing member 80 can be reduced, resulting in reduced equipment costs. Furthermore, the reduction in welding points can also reduce the cost of non-destructive testing, the time required for rework to repair welding defects, and the risk of damage due to inherent defects.

The inner end of the blade 60 faces the internal space S1. In this way, the inner end of the blade 60 that fixes the reinforcing member 80 faces a relatively large space, which improves the workability of fixing the blade 60 and the reinforcing member 80.

In addition, in this embodiment, the reinforcing member 80 is fixed to the inner end of the blade 60. As a result, compared to when the reinforcing member 80 is fixed to the radial outer end or plate surface (collision surface 61 or back surface 65) of the blade 60, for example, the solid fuel guided from the radial outside is less likely to come into contact with the reinforcing member 80. Therefore, wear of the reinforcing member 80 due to the solid fuel can be suppressed.

The reinforcing member 80 is fixed to the inner end of the blade 60. This allows a structure in which the reinforcing member 80 is not fixed to the plate surface (collision surface 61) of the blade 60. This makes it possible to make it difficult for the reinforcing member 80 to impede the flow of solid fuel classified by the blade 60. This allows for improved classification accuracy compared to when the reinforcing member 80 is fixed to the plate surface (collision surface 61) or outer end (e.g., the side surface 68 on the outer periphery) of the blade 60.

In addition, in this embodiment, the reinforcing member 80 is annular. This allows the reinforcing member 80 to withstand the tensile force caused by centrifugal force, so that the blade 60 can be more appropriately reinforced and deflection can be suppressed. Furthermore, when attaching the reinforcing member 80, the task of cutting the reinforcing member 80 into multiple pieces to match the spacing of the blade 60 can be omitted.

Second Embodiment
Next, a second embodiment of the present disclosure will be described with reference to Fig. 5 and Fig. 6. In this embodiment, only the reinforcing member is different from the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

As shown in FIG. 5, the reinforcing member 180 according to this embodiment is formed in an annular shape by connecting a plurality of arc-shaped (three in this embodiment as an example) divided reinforcing members (divided parts) 180a. Each divided reinforcing member 180a has a 120-degree arc shape. Each divided reinforcing member 180a does not have to be divided evenly. The divided reinforcing members 180a are arranged in a circumferential direction to form a ring. As shown in FIG. 6, the divided reinforcing members 180a are connected at their circumferential ends by a welded part W2. That is, the divided reinforcing members 180a are connected to each other by welding. In addition, a groove 181 is formed at the circumferential end of each divided reinforcing member 180a. Specifically, as shown in FIG. 6, the groove 181 is formed so that a groove recessed from the inner circumferential surface to the outer circumferential surface is formed when the divided reinforcing members 180a are butted against each other. In this embodiment, as shown in FIG. 6, the split reinforcement members 180a are fixed together by welding so that the welded portion W2 enters the groove 181.

According to this embodiment, the following advantageous effects are obtained.
In this embodiment, the reinforcing member 180 has a plurality of divided reinforcing members 180a. In other words, the annular reinforcing member 180 is divided into a plurality of divided reinforcing members 180a. This allows the single member to be made smaller than when the reinforcing member 180 is made up of a single member, and therefore simplifies the task of fixing the reinforcing member 180 and the blade 60.

The method of connecting the multiple divided reinforcement members 180a on the arc is not limited to the method described above. For example, as shown in FIG. 7, the divided reinforcement members 180a may be connected to each other with a joint structure 185. The joint structure 185 is a so-called dovetail joint. The joint structure 185 has a convex portion 185a provided at the circumferential end of one of the divided reinforcement members 180a to be connected, and a concave portion 185b provided at the circumferential end of the other divided reinforcement member 180a and engaging with the convex portion 185a. Since the joint structure 185 is a so-called dovetail joint, the concave portion 185b and the convex portion 185a are provided only on the inner circumferential side of each divided reinforcement member 180a. The outer circumferential side of each divided reinforcement member 180a is simply butted against the end faces, and no concave portion 185b or convex portion 185a is provided. That is, the recess 185b is formed so as to be recessed from the inner peripheral surface and end surface of the split reinforcing member 180a. The joint structure 185 is configured so that the protrusion 185a can be fitted into the recess 185b from the inner peripheral side, but cannot be fitted from the outer peripheral side.

By providing the convex portion 185a and the concave portion 185b only on the inner circumferential side in this manner, even if the reinforcing member 180 is worn from the outer circumferential side, the convex portion 185a and the concave portion 185b can be made difficult to be damaged. Therefore, the connection between the divided reinforcing members 180a can be made difficult to be released.
The joint structure 185 that connects the divided reinforcing members 180a to each other is not limited to a dovetail joint. The joint structure that connects the divided reinforcing members 180a to each other may be another type of joint, for example, a screw joint.

Third Embodiment
Next, a third embodiment of the present disclosure will be described with reference to Figures 8 and 9. This embodiment differs from the first embodiment only in that the blade is covered with a material having wear resistance. The same components as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

8 and 9, the entire impact surface 61 of the blade 60 according to this embodiment is covered with a hardened buildup plate (wear-resistant portion) 190 made of a high-hardness material having wear resistance. In other words, in this embodiment, the blade 60 and the hardened buildup plate 190 overlap in the plate thickness direction. The length of the blade 60 in the plate thickness direction and the length of the hardened buildup plate 190 in the plate thickness direction may be approximately the same. The hardened buildup plate 190 is made of a material that is harder than the material of the blade 60. Examples of the material of the blade 60 include stainless steel material, etc. Examples of the material of the hardened buildup plate 190 include high-chromium cast iron material, etc.

Note that the welded portion W1 is provided only on the blade 60 and not on the hardening plate 190.

According to this embodiment, the following advantageous effects are obtained.
Generally, welding cannot be performed on the hardening plate 190 formed of a high hardness material, but in this embodiment, since the reinforcing member 80 is fixed to the inner end of the blade 60, it is possible to have a structure in which the reinforcing member 80 is not fixed to the collision surface 61 of the blade 60. Therefore, in the blade 60 provided with the reinforcing member 80, the collision surface 61 can be covered with the hardening plate 190.

In addition, in this embodiment, the impact surface 61 of the blade 60 is covered with a hardened buildup plate 190 made of a wear-resistant material. This makes it possible to suppress wear on the impact surface 61 of the blade 60.

In addition, in this embodiment, since the reinforcing member 80 is fixed to the inner end of the blade 60, the reinforcing member 80 is not fixed to the collision surface 61 of the blade 60. Therefore, compared to the case where the reinforcing member 80 is fixed to the collision surface 61, the collision surface 61 can be easily covered with the hardening plate 190.

The present disclosure is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present disclosure.
For example, in the above-described embodiment, the mill of the present disclosure is used, but the solid fuel may be biomass fuel or PC (Petroleum Coke) fuel generated during oil refining, or a combination of these fuels may be used. Also, the high hardness material having wear resistance over the entire surface of the impact surface 61 is not limited to a hardened buildup plate, and a ceramic plate, for example, may be used.

In the above embodiment, an example of applying the classifier of the present disclosure to a mill that pulverizes solid fuel has been described, but the present disclosure is not limited to this. For example, the classifier of the present disclosure may be applied to a pulverizer that pulverizes ore.

In addition, in each of the above embodiments, an example has been described in which the reinforcing member 80 and the blade 60 are fixed by welding, but the present disclosure is not limited to this. For example, the reinforcing member 80 and the blade 60 may be fixed by a fastener such as a bolt. Also, the reinforcing member 80 and the blade 60 may be fixed via a fixing member such as a bracket.

In addition, in each of the above embodiments, an example has been described in which the cross-sectional shape of the reinforcing member 80 is substantially circular, but the present disclosure is not limited to this. The cross-sectional shape of the reinforcing member may be any shape that can sufficiently suppress deformation due to centrifugal force, and may be, for example, an oval or elliptical shape. It may also be a polygonal shape.

The reinforcing member 80 may also have a hanging piece, an eye plate, or the like, provided on the upper surface. With this configuration, the reinforcing member 80 can be lifted by engaging a hook or the like provided on a lifting device (not shown) with the hanging piece or eye plate. Therefore, the reinforcing member 80 can be lifted to a desired height, which simplifies the work of fixing the reinforcing member 80 and the blade 60. Examples of the lifting device include a crane and a winch.

In addition, in each of the above embodiments, an example in which the reinforcing member 80 is annular has been described, but the present disclosure is not limited to this. For example, the reinforcing member may be an annular polygonal shape in plan view. Specifically, for example, the reinforcing member may be an annular polygonal shape with the same number of vertices as the number of blades 60.

In addition, in each of the above embodiments, an example has been described in which the reinforcing member 80 is provided in the center of the blade 60 in the vertical direction, but the present disclosure is not limited to this. For example, the reinforcing member 80 may be fixed in a position in the vertical direction where the greatest centrifugal force acts on the blade 60. By configuring in this manner, the reinforcing member 80 can be fixed in a position where it is most likely to deform due to the centrifugal force of the blade 60. Therefore, deformation of the blade 60 can be suitably suppressed.

Specifically, for example, in each of the above embodiments, as shown in FIG. 2 etc., the blade 60 is inclined so that the upper part is farther away from the central axis C than the lower part. As a result, when the rotary classifier 16 rotates, the centrifugal force F1 (see FIG. 2) acting on the upper part of the blade 60 is greater than the centrifugal force F2 (see FIG. 2) acting on the lower part of the blade 60. In this way, the centrifugal force acting on the blade 60 is not uniform in the vertical direction. Taking this into consideration, the reinforcing member 80 may be provided at the vertical position of the blade 60 where the centrifugal force acting is the greatest. By providing it in this way, it is possible to further suppress deformation of the blade 60. The position where the centrifugal force acting on the blade 60 is the greatest is a position above the center in the vertical direction when the blade 60 is inclined so that the upper part is farther away from the central axis C than the lower part.

In addition, in each of the above embodiments, an example in which one reinforcing member 80 is provided has been described, but the present disclosure is not limited thereto. For example, a plurality of reinforcing members 80 may be provided. When a plurality of reinforcing members 80 are provided, they may be arranged so as to be lined up at a predetermined interval in the vertical direction. Specifically, for example, when two reinforcing members 80 are provided, one reinforcing member 80 may be provided at a position 1/3 from the top of the blade 60, and one reinforcing member 80 may be provided at a position 2/3 from the top of the blade 60. When a plurality of reinforcing members 80 are provided, the intervals between the reinforcing members 80 may be equal or unequal. For example, as described above, when the centrifugal force F1 (see FIG. 2) acting on the upper part of the blade 60 is greater than the centrifugal force F2 (see FIG. 2) acting on the lower part of the blade 60, the reinforcing members 80 may be provided so as to be biased toward the upper side.

The classifier, the power generation plant, and the method of operating the classifier described in the above-described embodiments can be understood, for example, as follows.
A classifier according to one aspect of the present disclosure is a classifier (16) that rotates about a central axis (C) extending in the vertical direction, classifies particles introduced from the radial outside by a carrier gas, and introduces the particles having a predetermined particle size or less into its interior, and includes a main body (70) that rotates about the central axis (C), a plurality of plate-shaped blades (60) that extend in the vertical direction and have upper and lower portions fixed to the main body (70), and a reinforcing member (80) that reinforces the plurality of blades (60), wherein the plurality of blades (60) are arranged side by side at a predetermined interval in the circumferential direction at positions spaced a predetermined distance outward in the radial direction from the central axis (C) so that plate surfaces of the blades (60) adjacent in the circumferential direction face each other, and the reinforcing member (80) is fixed to the radial inner ends of the blades (60) and connects the blades (60) that are arranged side by side in the circumferential direction.

In the above configuration, the reinforcing member is fixed to the inner end of the blade. Therefore, the reinforcing member can be fixed to one blade at one location. This reduces the number of fixing locations between the blade and the reinforcing member compared to a case where the reinforcing member is fixed to one blade at multiple locations. This simplifies the work of fixing the blade and the reinforcing member. As a result, the process of manufacturing the rotary classifier is shortened, and the work cost can be reduced.
In addition, since the number of fixing points between the blade and the reinforcing member can be reduced, the number of materials used to fix the blade and the reinforcing member (e.g., materials used for welding, fasteners, etc.) can be reduced, thereby reducing equipment costs.
In the above configuration, the reinforcing member is fixed to the inner end of the blade. This makes it difficult for the solid fuel guided from the outside in the radial direction to come into contact with the reinforcing member, compared to a case in which the reinforcing member is fixed to the outer end in the radial direction of the blade. This makes it possible to suppress wear of the reinforcing member due to the solid fuel.
In addition, the reinforcing member is fixed to the inner end of the blade. This allows a structure in which the reinforcing member is not fixed to the plate surface of the blade. Therefore, the reinforcing member is less likely to obstruct the flow of the solid fuel classified by the blade. Therefore, the classification accuracy can be improved compared to the case in which the reinforcing member is fixed to the plate surface of the blade.

In a classifier according to one aspect of the present disclosure, the reinforcing member (80) is annular and its outer circumferential surface is fixed to the blade (60).

In the above configuration, the reinforcing member is annular. This allows the reinforcing member to withstand the tensile force caused by centrifugal force, so the blade can be reinforced more effectively.

In a classifier according to one aspect of the present disclosure, the reinforcing member (80) has a plurality of division sections (180a) arranged side by side in the circumferential direction, and the ends of the division sections (180a) adjacent to each other in the circumferential direction are connected to each other.

In the above configuration, the reinforcing member has multiple divisions. In other words, the annular reinforcing member is divided into multiple divisions. This allows the single member to be made smaller than when the reinforcing member is made up of a single member, and simplifies the task of fixing the reinforcing member and the blade.

In one embodiment of the classifier disclosed herein, the plate surface (61) on the front side in the rotation direction of the blade (60) is covered with a wear-resistant portion (190) made of a material having wear resistance.

The pulverized solid fuel particles collide with the plate surface on the front side of the blade rotation direction. In the above configuration, the plate surface on the front side of the blade rotation direction is covered with a wear-resistant material. This makes it possible to suppress wear of the plate surface of the blade.
In addition, in the above-mentioned configuration, since the reinforcing member is fixed to the inner end of the blade, the reinforcing member is not fixed to the plate surface of the blade, and therefore the plate surface can be covered with an abrasion-resistant material more easily than in the case where the reinforcing member is fixed to the plate surface.

In a classifier according to one aspect of the present disclosure, the reinforcing member (80) is fixed in a position in the vertical direction where the greatest centrifugal force acts on the blade (60).

When the classifier rotates, centrifugal force acts on the blade. In the above configuration, the reinforcing member is fixed in a position in the vertical direction where the greatest centrifugal force acts on the blade. In other words, the reinforcing member is fixed in a position where it is most likely to deform due to centrifugal force. Therefore, deformation of the blade can be effectively suppressed.

A pulverizer according to one embodiment of the present disclosure is equipped with a classifier (16) described above.

The power plant according to one aspect of the present disclosure includes the pulverizer (10) described above, a boiler (200) that burns the pulverized solid fuel, which is particles pulverized by the pulverizer (10) and classified by the classifier (16) to have a particle size equal to or smaller than a predetermined particle size, and a power generation unit that generates power using steam generated by the boiler (200).

The method of operating a classifier according to one aspect of the present disclosure is a method of operating a classifier (16) that rotates about a central axis (C) extending in the vertical direction, classifies pulverized solid fuel particles introduced from the radial outside by a carrier gas, and introduces the pulverized particles having a predetermined particle size or less into the inside, and the classifier (16) comprises a main body (70) that rotates about the central axis (C), a plurality of plate-shaped blades (60) that extend in the vertical direction and have upper and lower portions fixed to the main body (70), and a reinforcing member (8) that reinforces the plurality of blades (60). 0), the blades (60) are arranged at a predetermined interval in the circumferential direction at a position spaced a predetermined distance from the central axis (C) toward the outside in the radial direction, so that the plate surfaces of the blades (60) adjacent in the circumferential direction face each other, the reinforcing member (80) is fixed to the inner end of the blade (60) in the radial direction and connects the blades (60) arranged in the circumferential direction to each other, and the blade (60) classifies the particles into particles larger than a predetermined particle diameter and particles having a predetermined particle diameter or less.

1: Power plant 10: Mill 11: Housing 12: Grinding table 13: Grinding roller 14: Drive unit 15: Mill motor 16: Rotary classifier (classifier)
17: Fuel supply section 18: Classifier motor 19: Outlet port 20: Coal feeder 21: Bunker 22: Conveyor section 23: Coal feeder motor 24: Downspout 30: Blower section 30a: Hot gas flow path 30b: Cold gas flow path 30c: Hot gas damper 30d: Cold gas damper 31: Primary air ventilator 32: Forced draft fan 34: Heat exchanger 40: Status detection section 41: Bottom surface section 42: Ceiling section 45: Journal head 47: Support arm 48: Support shaft 49: Pressing device 50: Control section 60: Blade 61: Collision surface 65: Back surface 68: Side surface 70: Main body section 71: Cylindrical shaft 72: Upper end 72a: Opening 73: Lower end 80: Reinforcement member 100: Solid fuel pulverizer 100a : Primary air flow passage 100b : Pulverized fuel supply passage 180 : Reinforcing member 180a : Divided reinforcing member (divided portion)
181: Groove 185: Joint structure 185a: Convex portion 185b: Concave portion 190: Hardened build-up plate (wear-resistant portion)
200: boiler 210: furnace 220: burner

Claims (7)

A classifier that rotates about a central axis extending in a vertical direction, classifies particles introduced from a radially outer side by a carrier gas, and introduces the particles having a predetermined particle size or smaller into an interior of the classifier,
A main body portion that rotates about the central axis line;
A plurality of plate-shaped blades extending in the vertical direction and having upper and lower portions fixed to the main body portion;
a reinforcing member having a constant cross-sectional shape along a circumferential direction and reinforcing the plurality of blades;
The plurality of blades are arranged at predetermined intervals in the circumferential direction at positions spaced apart from the central axis line on the radially outer side by a predetermined distance such that plate surfaces of the blades adjacent in the circumferential direction face each other,
the reinforcing member is annular , fixed to inner ends of the blades in the radial direction, and connects the blades arranged in the circumferential direction to each other,
an outer circumferential surface of the reinforcing member, which is annular, is connected to the inner end of the blade in the radial direction by a welded portion formed by welding;
The blade has a collision surface which is the plate surface on the front side in the rotation direction, a back surface which is the plate surface on the rear side in the rotation direction, and two side surfaces connecting the collision surface and the back surface,
The welded portions are provided on the radially inner side and back surface of the blade . The reinforcing member has a plurality of divided portions arranged side by side in the circumferential direction,
The classifier according to claim 1 , wherein ends of the divided portions adjacent to each other in the circumferential direction are connected to each other. 3. The classifier according to claim 1, wherein the collision surface on the front side in the rotation direction of the blade is covered with an abrasion-resistant portion made of an abrasion-resistant material. 4. The classifier according to claim 1 , wherein the reinforcing member is fixed at a position in the vertical direction where the greatest centrifugal force acts on the blade. A pulverizer comprising the classifier according to any one of claims 1 to 4 . A crusher according to claim 5 ;
a boiler that burns the pulverized solid fuel, which is the particles having a predetermined particle size or less that have been pulverized by the pulverizer and classified by the classifier;
a power generation unit that generates electricity using the steam generated by the boiler. A method for operating a classifier that rotates about a central axis extending in a vertical direction, classifies particles introduced from a radially outer side by a carrier gas, and introduces the particles having a predetermined particle size or smaller into the inside of the classifier, comprising the steps of:
The classifier comprises:
A main body portion that rotates about the central axis line;
A plurality of plate-shaped blades extending in the vertical direction and having upper and lower portions fixed to the main body portion;
a reinforcing member having a constant cross-sectional shape along a circumferential direction and reinforcing the plurality of blades;
The plurality of blades are arranged at predetermined intervals in the circumferential direction at positions spaced apart from the central axis line on the radially outer side by a predetermined distance such that plate surfaces of the blades adjacent in the circumferential direction face each other,
the reinforcing member is annular , fixed to inner ends of the blades in the radial direction, and connects the blades arranged in the circumferential direction to each other,
an outer circumferential surface of the reinforcing member, which is annular, is connected to the inner end of the blade in the radial direction by a welded portion formed by welding;
The blade has a collision surface which is the plate surface on the front side in the rotation direction, a back surface which is the plate surface on the rear side in the rotation direction, and two side surfaces connecting the collision surface and the back surface,
The welded portion is provided on the radially inner side surface and the rear surface of the blade,
A method for operating a classifier comprising a step of classifying the particles by the blade into particles larger than a predetermined particle size and particles having a predetermined particle size or smaller.