KR20210021917A - Solid fuel grinding apparatus, power generation plant, and control method for solid fuel grinding apparatus - Google Patents

Abstract

The present invention is to properly remove the pulverized fuel deposited inside a rotary classifier without increasing the manufacturing cost of a mill or the weight of the rotary classifier. According to the present invention, provided is a solid fuel grinding apparatus comprising: a rotary table (12) to which solid fuel is supplied from a fuel supply unit (17); a coal feeder for supplying the solid fuel to the fuel supply unit (17); a pulverizing roller (13) for pulverizing the solid fuel between the same and the rotary table (12); the rotary classifier (16) having a plurality of blades (16a) rotating about a central axis of rotation; and a control unit which controls the rotation of the rotary table (12), the supply of the solid fuel by the coal feeder, and the rotation of the rotary classifier (16). In the fuel discharge period from stopping the supply of the solid fuel by the coal feeder until stopping the rotation of the rotary table (12), the control unit controls the rotary classifier (16) to perform a speed increase operation to temporarily increase the number of revolutions per unit time.

Description

A solid fuel pulverizing device, a power plant, and a control method of a solid fuel pulverizing device {SOLID FUEL GRINDING APPARATUS, POWER GENERATION PLANT, AND CONTROL METHOD FOR SOLID FUEL GRINDING APPARATUS}

The present disclosure relates to a solid fuel pulverizing device, a power plant, and a control method of a solid fuel pulverizing device.

Conventionally, solid fuels (carbon-containing solid fuels) such as coal or biomass fuel are pulverized into fine powders smaller than a predetermined particle diameter with a pulverizer (mill) and supplied to a combustion device. The mill is pulverized by crushing solid fuels such as coal or biomass fuel injected into the rotary table between the rotary table and the rollers, and crushed by the transport gas supplied from the outer periphery of the rotary table through the transport gas flow path. As a result, the finely powdered fuel is sorted out by a classifier and returned to a boiler for combustion in a combustion device. In a thermal power plant, steam is generated by heat exchange with combustion gas generated by combustion in a boiler, the steam turbine is rotationally driven by steam, and the generator connected to the steam turbine is rotationally driven to generate power.

The pulverized solid fuel (pulverized fuel) pulverized with a mill is classified into fine particles and granules by a rotary classifier installed at the top of the mill. The finely particulate fuel passes between the blades of the rotary classifier and is sent to a combustion device which is a post-process, and the granulated fuel collides with the blades of the rotary classifier, falls to the rotary table, and is pulverized again.

As a carbon-containing solid fuel, biomass fuels such as woody are difficult to pulverize finely, have high combustibility, and are capable of being suitably burned even with relatively large particle diameters. Therefore, when biomass fuel is used as a solid fuel, it is usually supplied from a mill to a combustion apparatus provided in a boiler in a state of about 5 to 10 times larger particle diameter than that of coal.

As described above, since coal and biomass fuel have different particle diameters supplied to the combustion device, the mill for pulverizing and classifying solid fuel has a different design (e.g., housing shape) for pulverization of biomass fuel and coal pulverization. , The rotation speed of the rotary table, the rotation speed of the classifier, etc.), and it is preferable to individually design. However, from the viewpoint of equipment cost and installation space, the same mill can cope with solid fuels of both biomass fuel and coal, and using a mill capable of sharing the coal and biomass fuel, biomass fuel can be used. It is desired to be able to use it.

When coal is used as the solid fuel, the particle diameter after pulverization becomes small and uniform (about 100 µm). Therefore, a bridge (a phenomenon in which an arc structure is formed between powders to close the gap) between the blades of the rotary classifier is unlikely to occur. In addition, since the angle of repose of the pulverized coal (pulverized coal) is relatively small (about 40° to 45°), it is often dropped on the rotating table without being deposited inside the rotary classifier.

On the other hand, when biomass fuel is used as the solid fuel, the biomass fuel is fibrous, and the particle diameter after pulverization becomes large and uneven (about 0.6 mm to 1 mm). Therefore, a bridge may occur between the blades of the rotary classifier. In addition, since the angle of repose of the pulverized biomass fuel is relatively large (about 60°), it is likely to be deposited inside the rotary classifier.

In addition, when biomass fuel is used as the solid fuel, the particle diameter after pulverization is larger than that of coal, and it is difficult to pass through the rotary classifier. Therefore, the rotation speed of the rotary classifier when using biomass fuel (for example, 10 rpm to 30 rpm) is more than the rotation speed of the rotary classifier when using coal (for example, 90 rpm to 180 rpm). By lowering it, there are cases in which the dischargeability of the pulverized biomass fuel is secured. In this case, in the case of using biomass fuel, the centrifugal force acting on the biomass fuel deposited inside the rotary classifier is reduced, and the deposition of the biomass fuel is more likely to proceed. If the pulverized biomass fuel is excessively deposited in the rotary classifier, the pulverized biomass fuel is inhibited from being transported to the boiler. Therefore, it may be necessary to periodically perform cleaning work to remove the biomass fuel deposited inside the rotary classifier.

For a problem in the case of using biomass fuel as a solid fuel, a mill provided with a gas injection mechanism for removing biomass fuel by injecting gas into biomass fuel deposited inside a rotary classifier has been proposed (e.g. For example, see Patent Document 1).

Japanese Patent Publication No. 2015-205245

However, in the mill of Patent Document 1, since it is necessary to provide a gas injection mechanism inside the rotary classifier, the manufacturing cost of the mill increases and the weight of the rotary classifier increases.

The present disclosure has been made in view of these circumstances, and without increasing the manufacturing cost of the mill or the weight of the rotary classifier, a solid fuel pulverizing device capable of appropriately removing fuel after pulverization deposited in the rotary classifier, and this It is an object of the present invention to provide a power plant equipped and a method for controlling a solid fuel pulverizing device.

A solid fuel pulverizing device according to an aspect of the present disclosure includes a rotary table rotating around a rotational central axis while supplying solid fuel from a fuel supply unit, a fuel supply unit for supplying the solid fuel to the fuel supply unit, and the rotary table And a crushing roller for pulverizing the solid fuel between and, and a plurality of classification blades that are rotated around the rotational center axis and provided at predetermined intervals around the rotational center axis, and the solid fuel is pulverized A rotary classifier for classifying fuel after, and a control unit for controlling rotation of the rotary table, supply of the solid fuel by the fuel supplier, and rotation of the rotary classifier, wherein the control unit comprises: In the fuel discharge period from stopping the supply of solid fuel until stopping the rotation of the rotary table, control is performed to perform an increase in speed operation for temporarily increasing the number of rotations per unit time of the rotary classifier.

A method for controlling a solid fuel pulverizing device according to an aspect of the present disclosure includes a rotary table that rotates around a rotational central axis while supplying solid fuel from a fuel supply unit, and a fuel supply unit for supplying the solid fuel to the fuel supply unit, A crushing roller for pulverizing the solid fuel between the rotary table and a plurality of classification blades rotating around the rotation center axis and provided at predetermined intervals around the rotation center axis, wherein the solid fuel is A solid fuel pulverization apparatus having a rotary classifier for classifying fuel after pulverization, comprising: a first stop step of stopping supply of the solid fuel by the fuel supply; and supply of the solid fuel in the first stop step A second stop step of stopping the rotation of the rotary table after a fuel discharge period elapses after stopping the fuel, and an increase step of temporarily increasing the number of rotations per unit time of the rotary classifier in the fuel discharge period. Equipped.

Solid fuel pulverization device capable of appropriately removing fuel after pulverization deposited in the rotary classifier without increasing the manufacturing cost of the mill or the weight of the rotary classifier, power plant equipped with the same, and control of the solid fuel pulverization device Can provide a way.

1 is a schematic configuration diagram showing a power plant according to a first embodiment of the present disclosure.
2 is a longitudinal sectional view schematically showing the mill shown in FIG. 1.
3 is a longitudinal sectional view showing the periphery of the installation position of the downstream detection tube.
4 is a partially enlarged view of the rotary classifier shown in FIG. 2.
5 is a diagram showing the relationship between the rotation speed of the rotary classifier and the discharge time of the accumulated fuel, and the relationship between the rotation speed of the rotary classifier and the centrifugal force applied to the accumulated fuel.
6 is a flowchart showing a process executed by the solid fuel pulverizing apparatus according to the first embodiment of the present disclosure.
7 is a flowchart showing a process executed by the solid fuel pulverizing apparatus according to the first embodiment of the present disclosure.
8 is a flowchart showing a process executed by the solid fuel pulverizing device according to the first embodiment of the present disclosure.
9 is a graph showing a change in the amount of fuel supplied by the feeder when the operation of the solid fuel pulverizing device according to the first embodiment is stopped.
10 is a graph showing a change in the number of revolutions per unit time of the rotary classifier when the operation of the solid fuel pulverizing device according to the first embodiment is stopped.
11 is a graph showing a change in the number of revolutions per unit time of the rotary table when the operation of the solid fuel pulverizing device according to the first embodiment is stopped.
12 is a graph showing a change in the flow rate of primary air supplied to the mill when the operation of the solid fuel pulverizing device according to the first embodiment is stopped.
13 is a graph showing a change in the amount of fuel on the rotary table when the operation of the solid fuel pulverizing device according to the first embodiment is stopped.
14 is a graph showing a change in the number of revolutions per unit time of the rotary classifier when the operation of the solid fuel pulverizing device according to the second embodiment is stopped.
15 is a graph showing a change in the amount of fuel on the rotary table when the operation of the solid fuel pulverizing device according to the second embodiment is stopped.

[First embodiment]

Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings. 1 is a schematic configuration diagram showing a power plant 1 according to a first embodiment of the present disclosure. FIG. 2 is a longitudinal sectional view schematically showing the mill 10 shown in FIG. 1.

<Overall configuration of power plant (1)>

The power generation plant 1 according to the present embodiment includes a solid fuel pulverizing device 100 and a boiler 200.

The solid fuel pulverization device 100 pulverizes solid fuel (carbon-containing solid fuel) such as coal or biomass fuel, as an example, and generates particulate fuel to the burner unit (combustion device) 220 of the boiler 200. It is a device that supplies. The power generation plant 1 including the solid fuel pulverization device 100 and the boiler 200 shown in FIG. 1 is provided with one solid fuel pulverization device 100, but a plurality of one boiler 200 is provided. A system including a plurality of solid fuel pulverizing devices 100 corresponding to each of the burner units 220 may be employed.

The solid fuel pulverization device 100 of the present embodiment includes a mill (pulverization unit) 10, a feeder (fuel supply unit) 20, a blower unit (transport gas supply unit) 30, and a state detection unit ( 40) and a control unit (determining unit) 50.

In addition, in the present embodiment, the upper direction indicates the vertical upper side, and the "upper" such as the upper part or the upper surface indicates a vertical upper part. In addition, similarly, "lower" represents a part of a vertical lower side.

The mill 10 for pulverizing solid fuel such as coal or biomass fuel supplied to the boiler 200 into pulverized solid fuel, which is a pulverized solid fuel, may be of a type that pulverizes only coal or only biomass fuel. Alternatively, biomass fuel may be pulverized together with coal.

Here, the biomass fuel is an organic resource derived from a renewable organism, for example, thinning wood, waste wood, driftwood, grass, waste, sludge, tires, and recycled fuels (pellets or chips) using these as raw materials, and the like. It is not limited to what is presented. Since biomass fuel is a carbon neutral that does not emit carbon dioxide, which is a global warming gas, from the point of introducing carbon dioxide in the process of growing biomass, its use has been studied in various ways.

The mill 10 includes a housing 11, a rotary table 12, a roller 13 (crushing roller), a drive unit 14, a rotary classifier 16, a fuel supply unit 17, and It is provided with a motor 18 for rotationally driving the rotary classifier 16.

The housing 11 is generally formed extending in the vertical direction, and is a housing that accommodates the rotary table 12, the roller 13, the rotary classifier 16, and the fuel supply unit 17. In the central portion of the ceiling portion 42 of the housing 11, a fuel supply portion 17 is provided. The fuel supply unit 17 supplies solid fuel derived from the bunker 21 into the housing 11, is arranged in the vertical direction at the center position of the housing 11, and the lower end extends to the inside of the housing 11 Installed.

In the vicinity of the bottom portion 41 of the housing 11, a driving unit 14 is provided, and a rotary table 12 that rotates by a driving force transmitted from the driving unit 14 is arranged rotatably.

The rotary table 12 is a circular member in plan view, and is disposed so as to face the lower end of the fuel supply unit 17. The upper surface of the rotary table 12 may have a low center portion and an inclined shape that increases toward the outside, and may have a shape in which the outer peripheral portion is curved upward. The fuel supply unit 17 supplies solid fuel (for example, coal or biomass fuel in this embodiment) from the upper side toward the lower rotary table 12, and the rotary table 12 supplies the supplied solid fuel. By grinding between the rollers 13, it is also called a grinding table.

When solid fuel is injected from the fuel supply unit 17 toward the center of the rotary table 12, the solid fuel is guided to the outer circumferential side of the rotary table 12 by the centrifugal force caused by the rotation of the rotary table 12, and the roller 13 ) And crushed. The pulverized solid fuel (fuel after pulverization) is upwards by the transport gas (hereinafter referred to as primary air) guided from the transport gas flow path (hereinafter, referred to as the primary air flow path) 100a. Is blown up and guided to the rotary classifier 16.

That is, on the outer periphery of the rotary table 12, a jet port (not shown) is provided through which primary air flowing in from the primary air flow path 100a flows out into the space above the rotary table 12 in the housing 11. . A vane (not shown) is installed at the ejection port, and a swirling force is applied to the primary air ejected from the ejection port. The primary air to which the swirling force is applied by the vanes becomes an airflow having a swirling speed component, and guides the solid fuel pulverized on the rotary table 12 to the rotary classifier 16 above the housing 11. In addition, among the pulverized solid fuel mixed with the primary air, those larger than a predetermined particle diameter are classified by the rotary classifier 16, or fall without reaching the rotary classifier 16, and fall to the rotary table 12. Returns to, and is crushed again.

The roller 13 is a rotating body for pulverizing the solid fuel supplied from the fuel supply unit 17 to the rotary table 12. The roller 13 is pressed against the upper surface of the rotary table 12 and cooperates with the rotary table 12 to pulverize the solid fuel. In FIG. 1, only one roller 13 is shown as a representative, but a plurality of rollers 13 are arranged to face each other at regular intervals in the circumferential direction so as to press the upper surface of the rotary table 12. For example, with an angular interval of 120° on the outer circumferential portion, three rollers 13 are arranged at equal intervals in the circumferential direction. In this case, a portion of the three rollers 13 in contact with the upper surface of the rotary table 12 (part to be pressed) has an equidistant distance from the rotation center axis of the rotary table 12.

The roller 13 is able to swing up and down by the journal head 45, and is supported so as to be accessible and spaced apart from the upper surface of the rotary table 12. When the rotary table 12 rotates with the outer peripheral surface in contact with the upper surface of the rotary table 12, the roller 13 receives a rotational force from the rotary table 12 and rotates together. When solid fuel is supplied from the fuel supply unit 17, the solid fuel is pressed between the roller 13 and the rotary table 12 to be pulverized to obtain a pulverized fuel.

The support arm 47 of the journal head 45 is capable of swinging in the vertical direction of the roller with the support shaft 48 as the center on the side surface of the housing 11 by the support shaft 48 along the horizontal direction. It is supported. In addition, a pressing device 49 is provided at the upper end of the support arm 47 on the vertically upper side. The pressing device 49 is fixed to the housing 11 and applies a load to the roller 13 via a support arm 47 or the like so as to press the roller 13 against the rotary table 12.

The drive unit 14 is a device that transmits a driving force to the rotary table 12 and rotates the rotary table 12 around a central axis. The drive unit 14 generates a driving force that rotates the rotary table 12.

The rotary classifier 16 is provided on the upper part of the housing 11 and has a hollow substantially inverted conical shape. The rotary classifier 16 is provided with a plurality of blades 16a extending in the vertical direction at its outer circumferential position. Each blade 16a is provided around the central axis of the rotary classifier 16 at predetermined intervals (equal intervals). In addition, the rotary classifier 16 uses the solid fuel pulverized by the roller 13 to be larger than a predetermined particle diameter (for example, 70 to 100 μm in coal) (hereinafter, pulverized solid fuel exceeding the predetermined particle diameter). Is a device that classifies pulverized solid fuel having a predetermined particle diameter or less (hereinafter referred to as a “fine powder fuel”) with a particle size of less than or equal to a predetermined particle size. The rotary classifier 16 classified by rotation is also called a rotary separator, and a rotational driving force is applied by a motor 18 controlled by the control unit 50, and a cylindrical shaft extending in the vertical direction of the housing 11 It rotates around the fuel supply unit 17 around (not shown).

The pulverized solid fuel that has reached the rotary classifier 16 is the relative balance between the centrifugal force generated by the rotation of the blade 16a and the centrifugal force due to the airflow of the primary air. It is knocked off by (16a), returned to the rotary table 12 and pulverized again, and the pulverized fuel is guided to the outlet 19 at the ceiling 42 of the housing 11.

The finely divided fuel classified by the rotary classifier 16 is discharged from the outlet 19 to the supply flow path 100b, and is conveyed together with the primary air to a post process. The pulverized fuel flowing out through the supply passage 100b is supplied to the burner unit 220 of the boiler 200.

The fuel supply unit 17 is installed with a lower end extending to the inside of the housing 11 along an up-down direction so as to penetrate the upper end of the housing 11, and the solid fuel injected from the upper portion of the fuel supply unit 17 is supplied to the rotary table 12 ) In approximately the center of the area. The fuel supply unit 17 is supplied with solid fuel from the feeder 20.

The feeder 20 includes a conveyance unit 22 and a motor 23. The conveying part 22 conveys the solid fuel discharged from the lower end of the down spout part 24 just below the bunker 21 by the driving force applied from the motor 23, and the fuel supply part of the mill 10 Lead to (17). Usually, the inside of the mill 10 is supplied with primary air for conveying the pulverized solid fuel, which is the pulverized fuel, and the pressure is increased. The down spout portion 24, which is a pipe extending in the vertical direction immediately under the bunker 21, holds fuel in a stacked state, and by the solid fuel layer stacked in the down spout portion 24, the mill The sealability of the (10) side's primary air and pulverized fuel from flowing back is ensured. The supply amount of the solid fuel supplied to the mill 10 may be adjusted to the belt speed of the belt conveyor of the conveying unit 22.

On the other hand, chips or pellets of biomass fuel before pulverization have a constant particle diameter compared to coal fuel (i.e., the particle diameter of the coal before pulverization is, for example, about 2 to 50 mm) (the size of the pellet is, for example, For example, the diameter is about 6 to 8 mm, and the length is about 40 mm or less), and it is lightweight. For this reason, when the biomass fuel is stored in the down spout portion 24, the gap formed between the biomass fuels becomes larger than that of the coal fuel.

Therefore, since there is a gap between the chips or pellets of the biomass fuel in the down spout part 24, the primary air blown from the inside of the mill 10 and the pulverized fuel pass through the gap formed between each biomass fuel. Thus, there is a possibility that the pressure inside the mill 10 decreases. In addition, when the primary air blows through the reservoir portion of the bunker 21, the transportability of the biomass fuel is deteriorated, dust is generated, the bunker 21 and the down spout portion 24 are ignited, and the inside of the mill 10 When the pressure decreases, there is a possibility that various problems may occur in the operation of the mill 10 such as a decrease in the conveyance amount of the pulverized fuel. For this reason, a rotary valve (not shown) may be provided in the middle of the fuel supply unit 17 from the feeder 20 so as to suppress backflow caused by blowing up of the primary air and the pulverized fuel.

The blower 30 is a device for drying the solid fuel pulverized by the roller 13 and blowing primary air for supply to the rotary classifier 16 into the interior of the housing 11. The blower 30 includes a hot gas blower 30a, a cold gas blower 30b, a hot gas damper 30c, and a cold air in order to adjust the primary air blown to the housing 11 to an appropriate temperature. A gas damper 30d is provided.

The hot gas blower 30a is a blower that blows heated primary air supplied from a heat exchanger (heater) such as an air preheater. On the downstream side of the hot gas blower 30a, a hot gas damper 30c (first blowing part) is provided. The degree of opening of the thermal gas damper 30c is controlled by the control unit 50. The flow rate of the primary air blown by the hot gas blower 30a is determined by the degree of opening of the hot gas damper 30c.

The cold gas blower 30b is a blower that blows primary air, which is outside air at room temperature. A cold gas damper (second blower) 30d is provided on the downstream side of the cold gas blower 30b. The degree of opening of the cold gas damper 30d is controlled by the control unit 50. The flow rate of the primary air blown by the cold gas blower 30b is determined according to the degree of opening of the cold gas damper 30d.

The flow rate of the primary air is a flow rate of the sum of the flow rate of the primary air blown by the hot gas blower 30a and the flow rate of the primary air blown by the cold gas blower 30b, and the temperature of the primary air, It is determined by a mixing ratio of the primary air blown by the hot gas blower 30a and the primary air blown by the cold gas blower 30b, and is controlled by the control unit 50.

In addition, a part of the combustion gas discharged from the boiler 200 is guided to the primary air blown by the hot gas blower 30a through a gas recirculation ventilator (not shown) to form a mixer, so that the primary air flow path 100a You may adjust the oxygen concentration of the primary air flowing in from.

In this embodiment, measured or detected data is transmitted to the control unit 50 by the state detection unit 40 of the housing 11. The state detection unit 40 of the present embodiment is, for example, a differential pressure measuring means, a portion in which primary air flows into the mill 10 from the primary air flow path 100a and a supply flow path from the inside of the mill 10 ( In 100b), the differential pressure between the outlet 19 from which the primary air and the pulverized fuel are discharged is measured as the differential pressure in the mill 10. For example, by the classification performance of the rotary classifier 16, the increase or decrease of the circulation amount of pulverized solid fuel circulating in the mill 10 between the vicinity of the rotary classifier 16 and the vicinity of the rotary table 12 and thus The increase or decrease of the differential pressure in the mill 10 is changed. That is, the solid fuel supplied to the inside of the mill 10 can be managed by adjusting the pulverized fuel discharged from the outlet 19, so that the particle size of the pulverized fuel does not affect the combustibility of the burner unit 220. In a range that does not exist, a lot of pulverized fuel can be supplied to the burner unit 220 provided in the boiler 200.

In addition, the state detection unit 40 of the present embodiment is, for example, a temperature measuring means, in order to blow up the solid fuel pulverized by the roller 13 by the rotary classifier 16, inside the housing 11 The temperature of the supplied primary air and the temperature of the primary air from the inside of the housing 11 to the outlet 19 are detected, and the blower 30 is controlled so as not to exceed the upper limit temperature. In addition, since the primary air is cooled by conveying the pulverized material while drying it in the housing 11, the temperature at the outlet 19 from the upper space of the housing 11 is, for example, about 60 to 80 degrees. do.

The control unit 50 is a device that controls each unit of the solid fuel pulverizing device 100. The control unit 50 may control the rotational speed of the rotary table 12 with respect to the operation of the mill 10 by transmitting a driving instruction to the drive unit 14, for example. The control unit 50 adjusts the classification performance by transmitting a driving instruction to the motor 18 of the rotary classifier 16 and controlling the rotational speed, so that the differential pressure in the mill 10 is adjusted within a predetermined range. It is possible to stabilize the supply of pulverized fuel by optimizing it. In addition, the control unit 50 transmits a driving instruction to the motor 23 of the feeder 20, so that the transport unit 22 conveys the solid fuel and supplies the solid fuel to the fuel supply unit 17. The amount of supply can be adjusted. In addition, the control unit 50 controls the opening degree of the hot gas damper 30c and the cold gas damper 30d by transmitting the opening degree instruction to the blowing unit 30 to control the flow rate and temperature of the primary air. I can.

The control unit 50 is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. The series of processing for realizing various functions is, as an example, stored in a storage medium or the like in the form of a program, the CPU reads this program into a RAM or the like, and executes information processing/calculation processing, whereby various functions are Come true. In addition, the program may be pre-installed in a ROM or other storage medium, provided in a form stored in a computer-readable storage medium, or distributed through a wired or wireless communication means, and the like may be applied. . Computer-readable storage media are magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like.

Next, a boiler 200 that generates steam by burning by using the pulverized fuel supplied from the solid fuel pulverizing device 100 will be described.

The boiler 200 includes a furnace 210 and a burner unit 220.

The burner unit 220 is a device for forming a flame by burning the pulverized fuel using primary air containing pulverized fuel supplied from the supply passage 100b and secondary air supplied from a heat exchanger (not shown). to be. The combustion of the pulverized fuel is performed in the furnace 210, and the high-temperature combustion gas is discharged to the outside of the boiler 200 after passing through a heat exchanger (not shown) such as an evaporator, a superheater, and an economizer.

The combustion gas discharged from the boiler 200 is subjected to a predetermined treatment in an environmental device (a denitration device, an electric dust collector, etc., not shown), and heat exchange with outside air is performed in a heat exchanger (not shown) such as an air preheater, It is guided to a stack (not shown) through a manned ventilator (not shown) and discharged to the atmosphere. The outside air heated by heat exchange with the combustion gas in the heat exchanger is sent to the above-described hot gas blower 30a.

The water supply to each heat exchanger of the boiler 200 is heated by an economizer (not shown), and then further heated by an evaporator (not shown) and a superheater (not shown) to generate high-temperature and high-pressure steam, and a steam turbine that is a power generation unit. It is sent to (not shown) and drives the steam turbine rotationally, and power generation is performed by rotationally driving a generator (not shown) connected to the steam turbine.

<Differential pressure detection unit>

In FIG. 2, the differential pressure detection part 43 provided separately from the state detection part 40 is shown. The differential pressure detection unit 43 detects a differential pressure different from the mill differential pressure, which is a differential pressure between the upstream side (in the mill 10) and the downstream side (outlet 19) of the mill 10 measured by the state detection unit 40. . Specifically, the differential pressure detection unit 43 is the pressure in the inner (SP1) of the rotary classifier 16, which is the inner circumferential side of the blade 16a, and the outer circumferential side of the blade 16a, and the inside of the housing 11 (rotary type The differential pressure of the pressure of the outside (SP2) of the classifier 16 (hereinafter, this differential pressure is referred to as "classifier differential pressure") is measured.

More specifically, the differential pressure detection unit 43 includes an upstream side (outside SP2) and a downstream side (inside SP1) in the flow of primary air (carrying gas) containing fuel after the blade 16a is pulverized. Measure the differential pressure of )). As the differential pressure detection unit 43, for example, a digital manometer 43a is used. The measured value of the manometer 43a is transmitted to the control unit 50. In addition, the differential pressure detection unit 43 is not limited to a differential pressure gauge such as a digital manometer, but may be a differential pressure gauge of another type, and the upstream side and downstream side in the primary air flow containing fuel after the blade 16a is pulverized. A pressure gauge may be provided for each of the pressure gauges, and the difference between the pressure values measured by these pressure gauges may be obtained.

The differential pressure detection unit 43 is inserted from the outside of the mill body on the upstream side of the blade 16a and is inserted from the outside of the mill body on the downstream side of the blade 16a and the upstream detection tube 43b with one end opened. It has a downstream detection tube 43c through which one end is opened. In each of the upstream side detection tube 43b and the downstream side detection tube 43c, an on-off valve 43d is provided between the manometer 43a. The on-off valve 43d is opened when the differential pressure is measured, and is closed when the differential pressure is not measured. In addition, when the manometer 43a is replaced, the on-off valve 43d is closed. The opening/closing control of the on/off valve 43d may be performed by the control unit 50.

As shown in FIG. 2, in this embodiment, the lower end of each blade 16a is fixed by the fixing part 16b. At the bottom of the rotary classifier 16 including the fixing part 16b, a plurality of fixing parts 16b are provided with respect to the space SP3 vertically below the rotary classifier 16. In general, a blade ( Even if there is an assembled fuel (assembly) that has not been classified by 16a) and has entered the interior (SP1) of the rotary classifier 16, it falls from the gap between the plurality of fixing parts 16b to the rotary table 12, and from SP1. Is discharged.

On the other hand, there is a case where sufficient pulverization is not performed and the fuel after pulverization that enters the interior SP1 of the rotary classifier 16 is deposited as the accumulated fuel B1 upward from the plurality of fixing portions 16b. When a bridge is generated in the accumulated and assembled fuel B1 to close the gap between the plurality of fixing parts 16b, the accumulated and assembled fuel B1 increases the amount of accumulation from the lower side of each blade 16a toward the upper side. , Since the effective area for classification of the blade 16a is blocked, the classification performance of the rotary classifier 16 is deteriorated. In addition, when the accumulation amount of the accumulated fuel B1 increases from the lower side of the blade 16a to the upper side, the pressure loss increases and the differential pressure of the classifier in the upstream and downstream of the blade 16a increases. In the present embodiment, the control unit 50 monitors the differential pressure between the inside (SP1) and the outside (SP2) of the rotary classifier 16 obtained by the differential pressure detection unit 43.

In Fig. 3, an end of the downstream detection tube 43c on the opening side is shown. In this embodiment, the downstream detection tube 43c is inserted into the interior SP1 of the rotary classifier 16 from the opening 42a formed in the ceiling part 42 of the mill 10. The downstream detection tube 43c is airtightly fixed to the ceiling portion 42 of the mill 10 by, for example, a flange portion 46 with an O-ring 44 interposed therebetween. In addition, although FIG. 3 shows a state before the flange portion 46 is fixed, the flange portion 46 is fixed by a fixing bolt (not shown) when fixing. In this way, the downstream detection tube 43c can be easily separated by using the flange portion 46. Therefore, when it is not necessary to measure the pressure inside SP1 of the rotary classifier 16, the downstream detection tube 43c may be separated, and blockage by fuel after pulverization of the downstream detection tube 43c is prevented. can do.

The downstream detection tube 43c may be bent so that the open end 43c1 of the tip end faces a direction intersecting the upstream direction of the internal flow F1 toward the outlet 19 side. In this embodiment, it is formed by being bent in an L-shape from the inside SP1, and is provided so that the open end 43c1 of the tip faces toward the outlet 19 side, which is the downstream direction of the internal flow F1. Thereby, the influence of the dynamic pressure of the internal flow F1 of the rotary classifier 16 is reduced, so that the static pressure can be accurately measured. In addition, the direction of the open end 43c1 may be any direction as long as the influence of the dynamic pressure of the internal flow F1 of the rotary classifier 16 can be neglected. In this case, for example, the tip of the downstream detection pipe 43c may be a straight pipe facing vertically downward.

As shown in Fig. 3, a purge pipe 43e may be connected to the downstream detection pipe 43c. An air supply source (not shown) is connected to the upstream side of the purge pipe 43e. The purge air (purge fluid) can flow from the purge pipe 43e toward the open end 43c1 of the downstream detection pipe 43c. Thereby, it is possible to prevent the downstream detection tube 43c from being blocked by the fuel after pulverization contained in the flow F1 inside the classifier entering from the open end 43c1. Therefore, the purge air is not normally supplied, but is supplied when a blockage of the downstream detection tube 43c is detected. Moreover, you may make it supply purge air regularly. Further, as the purge fluid, an inert gas such as nitrogen may be used instead of air.

<Deposition of sedimentary assembly fuel (B1)>

4 is a partially enlarged view of the rotary classifier 16 shown in FIG. 2. As shown in Fig. 4, in the interior SP1 of the rotary classifier 16, for example, a situation in which the accumulation of the accumulated fuel B1 is deposited above the fixing portion 16b is schematically described. have. Fig. 4 shows a state in which the accumulation amount increases from the lower side of each blade 16a to the upper side, and a part of the effective area for classification of the blades 16a is blocked (hereinafter, also referred to as a bridge state). The rotational central axis X shown in FIG. 4 is an axis that serves as a center around which the rotary classifier 16 rotates, and extends along the vertical direction.

The deposited granulated fuel B1 shown in FIG. 4 is, for example, deposited granulated fuel obtained by pulverizing biomass fuel. The angle of repose of the accumulated fuel B1 is larger than the angle θ formed by the upper surface of the fixed portion 16b with the horizontal surface (for example, about 60°). Therefore, when the accumulated fuel B1 is deposited on the upper surface of the fixed portion 16b and a bridge is generated, it is likely to be deposited in the interior SP1 of the rotary classifier 16. When the bridge state shown in FIG. 4 is achieved, the effective area for classification of the blade 16a is blocked, and thus the classification performance of the rotary classifier 16 is deteriorated.

In the rotary classifier 16 in which the accumulated fuel B1 in a bridge state as shown in Fig. 4 is deposited inside SP1, the rotational speed Rc per unit time of the rotary classifier 16 The relationship between [rpm] and the time required to discharge the accumulated fuel (B1) from the inside (SP1) of the rotary classifier 16 to the outside (SP2) (hereinafter, also referred to as the discharge time) was investigated. . Further, the relationship between the rotational speed Rc [rpm] per unit time of the rotary classifier 16 and the centrifugal force applied to the accumulated and granulated fuel B1 was investigated.

5 shows the relationship between the number of revolutions per unit time (Rc) [rpm] of the rotary classifier 16 and the discharge time of the accumulated fuel B1 and the number of revolutions per unit time of the rotary classifier 16 (Rc). It is a figure showing the relationship between [rpm] and the centrifugal force applied to the accumulated fuel B1.

In FIG. 5, Rcmax represents the maximum rotational speed of the rotary classifier 16 driven by the motor 18. Rc1 represents the number of revolutions of the rotary classifier 16 in normal operation when pulverizing biomass fuel. Rc1 is set to a value of 5% to 30% of Rcmax, for example. Rc2 is a value of the number of revolutions at which the accumulated fuel B1 is effectively discharged from the inside (SP1) of the rotary classifier 16 to the outside (SP2), and the increase in speed to be described later when the biomass fuel is pulverized. It shows the number of revolutions of the rotary classifier 16 in operation. Rcb is a predetermined rotational speed indicating the rotational speed of the rotary classifier 16 when the accumulated fuel B1 in a bridge state starts to be discharged from the inside SP1 to the outside SP2 by the action of the centrifugal force. Fb represents the centrifugal force applied to the accumulated fuel B1 when the rotary classifier 16 rotates at a predetermined rotation speed Rcb.

As shown in Fig. 5, when the rotational speed of the rotary classifier 16 is lower than the predetermined rotational speed Rcb, the centrifugal force applied to the accumulated and assembled fuel B1 is smaller than Fb. In this case, since the centrifugal force applied to the accumulated and assembled fuel B1 is too small, the bridged state of the accumulated and assembled fuel B1 is maintained, and the accumulated and assembled fuel B1 is not discharged to the outside SP2. On the other hand, when the rotational speed of the rotary classifier 16 is greater than the predetermined rotational speed Rcb, the centrifugal force gradually increases more than Fb, and the discharge time of the accumulated fuel B1 is gradually shortened. This is because the state of the bridge of the accumulated and assembled fuel B1 begins to collapse by the action of the centrifugal force, and the accumulated and assembled fuel B1 starts to be discharged from the inside SP1 to the outside SP2.

From the above investigation results, the inventors found that by increasing the rotational speed of the rotary classifier 16 higher than the predetermined rotational speed Rcb, the state of the bridge of the accumulated and assembled fuel B1 began to collapse, and from the inside (SP1) to the outside (SP2). ). On the other hand, if the rotational speed of the rotary classifier 16 is higher than the rotational speed Rc1 in normal operation, the inflow amount of solid fuel pulverized by contact with the blade 16a from the outside (SP2) to the inside (SP1) It is known that this decreases. Therefore, the inventors suppressed the influence of the rotational speed of the rotary classifier 16 higher than Rc1, which is the rotational speed in the normal operation operation, while breaking the bridge state of the accumulated and assembled fuel B1, and A control method was devised to properly discharge (B1) from the inside (SP1) to the outside (SP2).

Hereinafter, a method of controlling the solid fuel pulverizing device 100 of the present embodiment will be described with reference to the drawings. 6, 7 and 8 are flowcharts showing processing executed by the solid fuel pulverizing apparatus 100 according to the present embodiment. Each of the processes shown in FIGS. 6 to 8 is a process executed during the operation of the solid fuel pulverizing device 100, and is performed by executing a control program by the control unit 50 included in the solid fuel pulverizing device 100.

9 is a graph showing a change in the amount of fuel supplied by the feeder 20 when the operation of the solid fuel pulverizing device 100 is stopped. 10 is a graph showing a change in the number of revolutions Rc per unit time of the rotary classifier 16 when the operation of the solid fuel pulverizing device 100 is stopped. 11 is a graph showing a change in the number of revolutions Rt per unit time of the rotary table 12 when the operation of the solid fuel pulverizing device 100 is stopped. 12 is a graph showing a change in the flow rate of primary air supplied to the mill 10 when the operation of the solid fuel pulverizing device 100 is stopped. 13 is a graph showing a change in the amount of fuel of the solid fuel loaded on the rotary table 12 when the operation of the solid fuel pulverizing device 100 is stopped.

9 to 13, time T1 is a time when the supply of the solid fuel to the mill 10 by the feeder 20 is stopped. Time T2 is a time at which the classifier increasing operation of the rotary classifier 16 is performed. Time T3 is a time at which the classifier deceleration operation of the rotary classifier 16 is performed. Time T4 is a time at which the rotation of the rotary classifier 16, the rotation of the rotary table 12, and the supply of primary air to the mill 10 stop. As shown in Fig. 10, the period from time T1 to time T4 is a fuel discharge period for discharging the pulverized fuel remaining inside the mill 10 when the operation of the solid fuel pulverizing device 100 is stopped. It becomes Pd and Pd'. The fuel discharge periods Pd and Pd' are set to, for example, 10 minutes to 30 minutes in the present embodiment.

The solid fuel pulverizing apparatus 100 of the present embodiment can use coal or biomass fuel as the solid fuel to be pulverized. The solid fuel pulverization apparatus 100 can execute a control mode according to the type of fuel when coal is used and when biomass fuel is used. Hereinafter, a control mode executed by the solid fuel pulverizing apparatus 100 when using biomass fuel is referred to as a first control mode, and a control mode executed by the solid fuel pulverizing apparatus 100 when using coal is defined. 2 This is called control mode.

The solid fuel pulverizing device 100 is provided with an operating device (not shown) for receiving an instruction for selecting a control mode from an operator. The control unit 50 of the solid fuel pulverizing device 100 is in a first control mode or a second control according to an instruction from a control device (not shown) of the power plant 1 or an instruction received from an operator through the operating device. Selectively run the mode.

In step S101 shown in Fig. 6, the control unit 50 determines whether or not the instruction received from the operator via the operating device is the first control mode (the second control mode). When it is determined that the instruction of the first control mode is received, the control unit 50 advances the process to step S102, and when it is determined that the instruction of the first control mode is not received, the control unit 50 issues an instruction of the second control mode. It is determined that it is accepted, and the process advances to step S111 shown in FIG. The processing executed in step S102 to step S110 is the processing in the first control mode. The processing executed from step S111 to step S115 is the processing in the second control mode.

First, the first control mode executed in step S102 to step S110 will be described.

In step S102, the control unit 50 controls to execute the first driving operation. The first driving operation is an operation of normal operation in the first control mode in which biomass fuel is used as the solid fuel. The control unit 50, in the first operation operation, the feeder 20 so that the fuel supply amount of the biomass fuel supplied by the feeder 20 becomes Wf1 shown in FIG. 9 according to the load required by the boiler 200, etc. ) To control.

In addition, the control unit 50, in the first operation operation, the motor 18 so that the number of revolutions Rc per unit time of the rotary classifier 16 becomes Rc1 shown in Fig. 10 suitable for pulverization of biomass fuel. Control. Further, in the first driving operation, the control unit 50 controls the driving unit 14 so that the number of revolutions Rt per unit time of the rotary table 12 becomes Rt1 shown in FIG. 11. In addition, in the first operation operation, the control unit 50 determines that the flow rate of the primary air supplied to the mill 10 by the blowing unit 30 is V1 shown in FIG. 12 according to the load required by the boiler 200 and the like. Controls the blower 30 so that it becomes.

In step S103, the control unit 50 determines whether an instruction from a control device (not shown) of the power plant 1 or an instruction to stop operation is received from an operator through the operation device, or whether a predetermined operation stop condition is satisfied. Is determined. If the determination result is yes, the control unit 50 advances the process to step S104, and if the determination result is no, it repeatedly executes step S103.

In step S104 (first stop step), the control unit 50 controls the feeder 20 to stop supply of the biomass fuel to the mill 10 by the feeder 20. When step S104 is executed, as shown in Fig. 9, the fuel supply amount of the feeder 20 gradually decreases from Wf1, the fuel supply is stopped at time T1, and the fuel supply amount becomes approximately zero.

In step S105, the control unit 50 determines whether or not the predetermined first conveyance period Pt1 has elapsed from the time T1, and if yes, the process proceeds to step S106, and if no, the control unit 50 determines again in step S105. The first conveyance period Pt1 is a period set in advance so that the biomass fuel remaining in the mill 10 is discharged from the outlet 19 to the supply flow path 100b to be equal to or less than a predetermined amount. The first conveyance period Pt1 is set to a predetermined period as, for example, 1/3 of the fuel discharge period Pd in the present embodiment. As shown in Fig. 13, the amount of biomass fuel on the rotary table 12 gradually decreases until the time T2 is reached, from Wt3 to Wt1.

In step S106 (speed-up process), the control unit 50 performs a classifier accelerating operation for increasing the number of revolutions Rc of the rotary classifier 16 at a time T2 at which the first conveyance period Pt1 has elapsed from the time T1. Run. When step S106 is executed, as shown in Fig. 10, the rotational speed Rc of the rotary classifier 16 increases from Rc1 during normal operation to Rc2.

Rc2 is a rotational speed equal to or higher than the predetermined rotational speed Rcb shown in FIG. 5, and a rotation at which the accumulated fuel B1 is effectively discharged from the inside (SP1) of the rotary classifier 16 to the outside (SP2). It is more preferable if it is a number. Rcb is the number of revolutions of the rotary classifier 16 when the accumulated fuel B1 in the bridge state starts to be discharged from the inside SP1 to the outside SP2 by the action of the centrifugal force. Since Rc2 is the rotational speed of Rcb or more, it is possible to reliably destroy the accumulated fuel B1 in a bridge state. As shown in Fig. 13, the amount of biomass fuel on the rotary table 12 gradually increases from time T2 to time T3 to become Wt2.

One of the factors in which the amount of biomass fuel on the rotary table 12 gradually increases is because the accumulated fuel B1 is discharged from the rotary classifier 16 to the rotary table 12. In addition, another factor in which the amount of biomass fuel on the rotary table 12 gradually increases is that the number of revolutions Rc of the rotary classifier 16 increases from Rc1 during normal operation to Rc2 during the acceleration period Ps. This is because it is difficult for fuel to flow into the rotary classifier 16 after pulverization from the outside (SP2) to the inside (SP1).

In step S107, the control unit 50 determines whether or not a predetermined acceleration period Ps has elapsed from the time T2, and if yes, the process proceeds to step S108, and if no, the control unit 50 determines again in step S107. The acceleration period Ps is a period set in advance so that the discharge of the accumulated fuel B1 in the inside SP1 of the rotary classifier 16 to the outside SP2 is completed. The acceleration period Ps is set to a predetermined period of 1/3 of the fuel discharge period Pd in the present embodiment, for example.

In step S108 (deceleration step), the control unit 50 executes a classifier deceleration operation for reducing the rotation speed Rc of the rotary classifier 16 at a time T3 at which the acceleration period Ps has elapsed from the time T2. . When step S108 is executed, as shown in Fig. 10, the rotational speed Rc of the rotary classifier 16 decreases from Rc2 during increased speed operation to, for example, Rc1 during normal operation. Although the rotational speed Rc of the rotary classifier 16 in the classifier deceleration operation decreases from Rc2, it may be greater than Rc1 during normal operation.

In step S109, the control unit 50 determines whether or not a predetermined second conveyance period Pt2 has elapsed from the time T3, and if yes, the process advances to step S110, and if no, the control unit 50 determines again in step S109. The second conveyance period Pt2 is a period set in advance so that the biomass fuel remaining inside the mill 10 is discharged from the outlet 19 to the supply flow path 100b to be equal to or less than a predetermined amount. The second conveyance period Pt2 is set to a predetermined period of 1/3 of the fuel discharge period Pd in the present embodiment, for example. As shown in Fig. 13, the amount of biomass fuel on the rotary table 12 gradually decreases from the time T3 to the time T4, and becomes smaller than that from Wt2 to Wt1.

One of the factors in which the amount of biomass fuel on the rotary table 12 gradually decreases is that the biomass fuel on the rotary table 12 that has increased in the acceleration period Ps is pulverized and the interior of the rotary classifier 16 (SP1). This is because it was once introduced into and discharged to the outside (SP2). That is, since it is a biomass fuel after pulverization, it is not necessary to provide a pulverization time, and it can be guided from the outside (SP2) of the rotary classifier 16 to the inside (SP1) in a short time. In addition, another factor in which the amount of biomass fuel on the rotary table 12 gradually decreases is that the pulverized biomass fuel that has fallen on the rotary table 12 is pulverized more finely in the acceleration period Ps.

In step S110 (second stop step), the control unit 50 operates the solid fuel pulverization device 100 because the fuel discharge period Pd has ended at the time T4 at which the second conveyance period Pt2 has elapsed from the time T3. Execute a stop operation to stop. The control unit 50 controls the motor 18 to stop the rotation of the rotary classifier 16 in the stop operation. Further, the control unit 50 controls the driving unit 14 to stop the rotation of the rotary table 12 in the stop operation.

Further, in the stop operation, the control unit 50 controls the blowing unit 30 to stop supply of primary air to the mill 10 by the blowing unit 30. In addition, it is not necessary to stop the supply of primary air, for example, when there is a request for supply of primary air from the boiler 200, when purging the volatile components generated in the mill 10, the burner unit In the case of supplying cooling air to 220 or the like, the blower 30 may be controlled so as to continue supply of the primary air. After executing step S110, the control unit 50 terminates the control of the solid fuel pulverizing device 100 according to the first control mode.

Next, the second control mode executed in steps S111 to S115 will be described. The second control mode is a mode executed when coal is used as solid fuel, and is a mode in which the rotational speed Rc of the rotary classifier 16 is maintained at a constant rotational speed Rc3 in the fuel discharge period Pd. Rc3 is set to a value of 60% to 90% of Rcmax, which is the maximum rotational speed of the rotary classifier 16, for example.

In step S111, the control unit 50 controls to execute the second driving operation. The second driving operation is an operation of normal operation in the second control mode in which coal is used as the solid fuel. In the second operation, the control unit 50 controls the feeder 20 so that the fuel supply amount of the coal supplied by the feeder 20 becomes Wf1 shown in FIG. 9 according to the load required by the boiler 200, etc. Control.

Further, in the second operation, the control unit 50 controls the motor 18 so that the number of revolutions Rc per unit time of the rotary classifier 16 becomes Rc3 shown in Fig. 10 suitable for pulverization of coal. do. Rc3 is higher than Rc1 during normal operation in the first control mode (when biomass fuel is used), and higher than Rc2 during speed-up operation in the first control mode. This is because the particle diameter of the biomass fuel after pulverization is larger than that of coal, and it is difficult to pass through the rotary classifier 16.

Further, in the second driving operation, the control unit 50 controls the driving unit 14 so that the number of revolutions Rt per unit time of the rotary table 12 becomes Rt2 shown in FIG. 11. The rotational speed Rt2 per unit time of the rotary table 12 may be the same as Rt1. In addition, in the second operation operation, the control unit 50 determines that the flow rate of the primary air supplied to the mill 10 by the blowing unit 30 is V2 shown in FIG. 12 according to the load required by the boiler 200 and the like. Controls the blower 30 so that it becomes. The flow rate V2 of the primary air may be the same as V1.

In step S112, the control unit 50 determines whether an instruction from a control device (not shown) of the power plant 1 or an instruction to stop operation is received from an operator through the operation device, or whether a predetermined operation stop condition is satisfied. Is determined. If the determination result is YES, the control unit 50 advances the process to step S113, and if the determination result is NO, repeats step S112.

In step S113, the control unit 50 controls the feeder 20 to stop the supply of coal to the mill 10 by the feeder 20. When step S113 is executed, as shown in Fig. 9, the fuel supply amount of the feeder 20 gradually decreases from Wf1, the fuel supply is stopped at time T1, and the fuel supply amount becomes approximately zero.

In step S114, the control unit 50 determines whether or not the fuel discharge period Pd' has elapsed from the time T1. If yes, the process proceeds to step S115, and if no, the control unit 50 determines again in step S114. The fuel discharge period Pd' is a period set in advance so that the coal remaining inside the mill 10 is discharged from the outlet 19 to the supply flow path 100b, and becomes equal to or less than a predetermined amount. As shown in Fig. 13, the coal on the rotary table 12 gradually decreases in the fuel discharge period Pd' from the time T1 to the time T4'. The fuel discharge period Pd' may be the same as Pd. In addition, the time T4' may be the same as the time T4.

In step S115, the control unit 50 executes a stop operation of stopping the operation of the solid fuel pulverizing device 100 at a time T4' after the fuel discharge period Pd' has elapsed from the time T1. The control unit 50 controls the motor 18 to stop the rotation of the rotary classifier 16 in the stop operation. Further, the control unit 50 controls the driving unit 14 to stop the rotation of the rotary table 12 in the stop operation. Further, in the stop operation, the control unit 50 controls the blowing unit 30 to stop supply of primary air to the mill 10 by the blowing unit 30.

In addition, it is not necessary to stop the supply of primary air, for example, when there is a request for supply of primary air from the boiler 200, when purging the volatile components generated in the mill 10, the burner unit In the case of supplying cooling air to 220 or the like, the blower 30 may be controlled so as to continue supply of the primary air. After executing step S115, the control unit 50 terminates the control of the solid fuel pulverizing device 100 in the second control mode.

The functions and effects exhibited by the solid fuel pulverizing device 100 of the present embodiment described above will be described.

According to the solid fuel pulverization device 100 of the present embodiment, the type of solid fuel is determined, and the supply of the solid fuel by the feeder 20 is stopped until the rotation of the rotary table 12 is stopped. In the fuel discharge period Pd, the rotational speed Rc of the rotary classifier 16 can be increased. In the case of solid fuel, for example, in the case of biomass fuel, in the case where there is a deposit of accumulated fuel B1 (fuel after pulverization) in the interior SP1 of the rotary classifier 16, the rotary classifier 16 The centrifugal force acting on the accumulated fuel B1 (fuel after pulverization) in the interior SP1 of the rotary classifier 16 increases as the number of revolutions Rc increases. Discharge from the rotary classifier 16 is promoted. Therefore, it is possible to appropriately remove the accumulated fuel B1 deposited in the interior SP1 of the rotary classifier 16 without increasing the manufacturing cost of the mill 10 or the weight of the rotary classifier 16. have.

In addition, according to the solid fuel pulverization device 100 according to the present disclosure, since the rotational speed Rc of the rotary classifier 16 is not increased in the predetermined first conveyance period Pt1 after the supply of the solid fuel is stopped, By using this first conveyance period Pt1, it is possible to promote the discharge of the accumulated and granulated fuel B1 remaining in the interior SP1 of the rotary classifier 16. Further, after the predetermined first conveyance period Pt1 has elapsed, the accumulated fuel B1 accumulated in the inside SP1 of the rotary classifier 16 can be appropriately removed and discharged to the outside SP2.

In addition, according to the solid fuel pulverization device 100 according to the present disclosure, the rotation speed Rc of the rotary classifier 16 is the prescribed rotation speed Rcb (the action of the centrifugal force) until the predetermined acceleration period Ps elapses. As a result, the accumulated fuel B1 in the bridge state is maintained above the rotational speed of the rotary classifier 16 when it starts to be discharged from the inside (SP1) to the outside (SP2). Accumulated fuel (B1) accumulated in (SP1) can be removed reliably.

In addition, according to the solid fuel pulverization apparatus 100 according to the present disclosure, since a predetermined second conveyance period Pt2 is provided after a predetermined acceleration period Ps, this second conveyance period Pt2 is used to prevent the rotary classifier 16. After pulverization, the fuel discharged from the inside is discharged from the outlet 19 to the supply flow path 100b, thereby promoting discharge to the outside of the apparatus.

[Second Embodiment]

Next, a second embodiment of the present disclosure will be described with reference to the drawings. This embodiment is a modified example of the first embodiment, and is assumed to be the same as the first embodiment, except for a case specifically described below, and the description below is omitted.

The solid fuel pulverization device 100 of the first embodiment increases the number of revolutions Rc of the rotary classifier 16 in the fuel discharge period Pd when executing the first control mode using biomass fuel. It was to execute the classifier increase operation only once. In contrast, the solid fuel pulverization device 100 of the present embodiment performs a classifier increasing operation for increasing the rotational speed Rc of the rotary classifier 16 when executing the first control mode using biomass fuel. It is to run it multiple times.

14 is a graph showing a change in the number of revolutions Rc per unit time of the rotary classifier 16 when the operation of the solid fuel pulverizing device 100 according to the present embodiment is stopped. 15 is a graph showing a change in the amount of fuel on the rotary table 12 when the operation of the solid fuel pulverizing device 100 according to the present embodiment is stopped. In Figs. 14 and 15, it is assumed that the fuel discharge period Pd' is the same as Pd, and the time T4' is the same as the time T4 in the second control mode.

As shown in Fig. 14, the solid fuel pulverization device 100 of the present embodiment is the one described in the first embodiment at the time T2 and the time T2b in the predetermined acceleration period Ps from the time T2 to the time T3. Execute the operation of increasing the supply air. In addition, the solid fuel pulverizing device 100 of the present embodiment performs the classifier deceleration operation described in the first embodiment at time T2a and time T3 in a predetermined acceleration period Ps.

In the solid fuel pulverization device 100 of the present embodiment, in the predetermined first conveyance period Pt1 from the time T1 to the time T2, the rotational speed Rc per unit time of the rotary classifier 16 is adjusted during normal operation. Keep at Rc1. The solid fuel pulverization device 100 performs a classifier increasing operation to increase the number of revolutions Rc per unit time of the rotary classifier 16 from Rc1 to Rc2 at time T2, and maintains Rc2 until time T2a. . The solid fuel pulverizing device 100 performs a classifier deceleration operation for reducing the rotational speed Rc from Rc2 to Rc1 at time T2a, and maintains Rc1 until time T2b. Further, at time T2a, the rotational speed Rc of the rotary classifier 16 in the classifier deceleration operation decreases from Rc2, but may be greater than Rc1 during normal operation.

The solid fuel pulverization device 100 performs a classifier increasing operation to increase the number of revolutions Rc per unit time of the rotary classifier 16 from Rc1 to Rc4 at time T2b, and maintains Rc4 until time T3. . The solid fuel pulverizing device 100 performs a classifier deceleration operation for reducing the rotational speed Rc from Rc4 to Rc1 at time T3, and maintains Rc1 until time T4. Here, Rc4 has a lower rotational speed than Rc2. This is because the state of the bridge of the accumulated fuel B1 collapses at the time T2, and the centrifugal force required to discharge the accumulated fuel B1 from the inside SP1 to the outside SP2 decreases after that. Further, at time T3, the rotational speed Rc of the rotary classifier 16 in the classifier deceleration operation decreases from R42, but may be greater than Rc1 during normal operation.

In the present embodiment, the number of revolutions Rc is not maintained above the predetermined number of revolutions Rcb over the entire period of the predetermined acceleration period Ps. From the time T2a to the time T2b, the number of revolutions Rc is less than Rcb. (In this embodiment, it is set to Rc1). This increases the number of times of changing the centrifugal force applied to the accumulated and assembled fuel B1 by repeating the speed-up operation and the deceleration operation a plurality of times to break the bridge state of the accumulated and assembled fuel B1, so that the accumulated and assembled fuel B1 is This is to facilitate discharge from the inside (SP1) to the outside (SP2).

As shown in Fig. 15, the amount of biomass fuel on the rotary table 12 gradually decreases until the time T2 is reached, and becomes Wt3 to Wt1. Further, the amount of biomass fuel on the rotary table 12 gradually increases from the time T2 to the time T2a to become Wt2. Further, the amount of biomass fuel on the rotary table 12 gradually decreases from the time T2a to the time T2b. Further, the amount of biomass fuel on the rotary table 12 gradually increases from the time T2b to the time T3. Further, the amount of biomass fuel on the rotary table 12 gradually decreases from the time T3 to the time T4 and becomes smaller than Wt1.

In addition, in the above description, when executing the first control mode using biomass fuel, in the fuel discharge period Pd, it is assumed that the classifier accelerating operation and the classifier deceleration operation are performed twice, but other modes may be used. . For example, three or more times of classifier increasing operation and a plurality of classifier deceleration operations may be performed.

In addition, in the above description, Rc4, which is the rotational speed Rc per unit time of the rotary classifier 16 in the period from time T2b to time T3, is set to be lower than Rc2, but other embodiments may be used. For example, the rotational speed Rc in the period from the time T2b to the time T3 may be made equal to Rc2, or may be higher than Rc2.

According to the solid fuel pulverization device 100 of the present embodiment described above, since the speed-up operation is performed a plurality of times in the fuel discharge period Pd, the accumulated fuel B1 deposited in the interior SP1 of the rotary classifier 16 ) By increasing the number of times of changing the centrifugal force applied to) and breaking down the bridge state of the deposited assembly fuel (B1), thereby facilitating the discharge of the deposited assembly fuel (B1) from the inside (SP1) to the outside (SP2). can do.

[Other Embodiment]

In the above description, the control unit 50 has decided to reduce the rotational speed Rc of the rotary classifier 16 to less than the predetermined rotational speed Rcb as the predetermined acceleration period Ps has elapsed. do. For example, the control unit 50 increases the number of revolutions per unit time of the rotary classifier 16 to Rc or more, and then the differential pressure detected by the differential pressure detection unit 43 becomes less than or equal to a predetermined differential pressure. The rotational speed Rc of the rotary classifier 16 may be reduced to less than the predetermined rotational speed Rcb.

According to such a solid fuel pulverizing device 100, by detecting the differential pressure between the inside (SP1) and the outside (SP2) of the rotary classifier 16 by the differential pressure detection unit 43, the inside (SP1) of the rotary classifier 16 It is possible to grasp the deposition situation of the sedimentary assembly fuel (B1) deposited in ). Then, the number of revolutions per unit time of the rotary classifier 16 as the differential pressure detected by the differential pressure detection unit 43 becomes less than or equal to the predetermined differential pressure and the accumulated fuel B1 deposited in the interior SP1 decreases. Can be reduced to less than a predetermined number of revolutions Rcb.

In addition, the control unit 50 rotates the rotational speed Rc of the rotary classifier 16 by a predetermined rotation as the predetermined acceleration period Ps has elapsed and the differential pressure detected by the differential pressure detection unit 43 becomes less than or equal to the predetermined differential pressure. It may be reduced to less than the number (Rcb). By doing so, even when the accumulated fuel B1 accumulated in the interior SP1 is not sufficiently reduced even after the acceleration period Ps has elapsed, the rotational speed Rc of the rotary classifier 16 is reduced to the predetermined rotational speed Rcb. When the differential pressure is maintained above and below the predetermined differential pressure, that is, when the accumulated and assembled fuel B1 is surely reduced, the rotational speed Rc of the rotary classifier 16 is less than the predetermined rotational speed Rcb. Can be reduced to

Further, the control unit 50 determines the amount of biomass fuel on the rotary table 12 based on the vertical differential pressure of the rotary table 12 or the lift amount of the roller 13, and the biomass fuel on the rotary table 12 The rotational speed Rc of the rotary classifier 16 may be reduced to less than the prescribed rotational speed Rcb, as the amount of is greater than or equal to the predetermined amount. In addition, it is determined that the amount of biomass fuel on the rotary table 12 is less than or equal to a predetermined amount, and a classifier increasing operation is performed to increase the number of revolutions Rc of the rotary classifier 16 to a predetermined number of revolutions Rcb or more. It may be performed, or the classifier deceleration operation may be performed after the lapse of a predetermined time thereafter, and the fuel discharge period Pd may be terminated.

In addition, the control unit 50 is a shorter time than a predetermined time due to a case in which it cannot respond within a predetermined time until the mill 10 is stopped due to the influence of the kind of biomass fuel, or depending on the operation status of the power plant 1. When it is necessary to stop the mill 10, the flow rate of the primary air supplied to the mill 10 may be increased in order to efficiently circulate fuel inside the mill 10. For example, when the fuel discharge period Pd is required more than a predetermined time (for example, 10 minutes to 30 minutes), the flow rate of the primary air is increased by a certain amount (for example, about 10% to 20% of the flow rate). You can do it.

In addition, in the above description, when increasing the number of revolutions Rc of the rotary classifier 16 to a predetermined number of revolutions Rcb or more in a predetermined speed increase period Ps, it is assumed that a constant speed is maintained for a predetermined time. It may be another aspect. For example, the rotational speed Rc of the rotary classifier 16 may be increased or decreased by a constant gradient. Further, for example, the rotational speed Rc of the rotary classifier 16 may be increased or decreased in stages.

In addition, in the above description, although it was assumed that the solid fuel used in the first control mode is biomass fuel, other aspects may be used. For example, PC (petroleum coke) generated during petroleum refining may be used. PC has a small and uniform particle diameter after pulverization, but the adhesion of the pulverized particles is high compared to coal or biomass fuel, and compared to coal, fuel may be deposited after pulverization in the interior (SP1) of the rotary classifier 16. There is. Therefore, it is effective to control by the first control mode of the present disclosure.

The solid fuel pulverizing device described in each of the embodiments described above is, for example, grasped as follows.

The solid fuel pulverization apparatus 100 according to the present disclosure includes a rotary table 12 rotating around a rotational central axis while supplying solid fuel from the fuel supply unit 17, and supplying solid fuel to the fuel supply unit 17. A pulverizing roller 13 for pulverizing solid fuel between the fuel feeder 20 and the rotary table 12, and a plurality of classifications arranged at predetermined intervals around the rotation center axis while rotating around the rotation center axis. A rotary classifier 16 having blades 16a and classifying fuel after pulverization of solid fuel is pulverized, rotation of the rotary table 12, supply of solid fuel by the fuel feeder 20 and the rotary classifier The control unit 50 is provided with a control unit 50 for controlling the rotation of 16, and the control unit 50 stops the supply of the solid fuel by the fuel supply unit 20 until the rotation of the rotary table 12 is stopped. In the fuel discharge period Pd, control is made to execute an increase-speed operation for temporarily increasing the number of revolutions Rc per unit time of the rotary classifier 16.

According to the solid fuel pulverization apparatus 100 according to the present disclosure, the fuel discharge period Pd from stopping the supply of the solid fuel by the fuel feeder 20 until the rotation of the rotary table 12 is stopped. Thus, the number of revolutions Rc per unit time of the rotary classifier 16 increases. As the number of revolutions per unit time of the rotary classifier 16 increases, the centrifugal force acting on the fuel after pulverization inside the rotary classifier 16 increases. By collapsing, the discharge of fuel from the rotary classifier 16 after pulverization is promoted. Therefore, it is possible to appropriately remove the fuel after pulverization deposited in the rotary classifier 16 without increasing the manufacturing cost of the mill 10 or the weight of the rotary classifier 16.

In the solid fuel pulverization apparatus 100 according to the present disclosure, the control unit 50 stops the supply of the solid fuel by the fuel supply unit 20, and then the first conveyance period Pt1 is the rotary classifier 16. After the number of revolutions per unit time (Rc) is less than the predetermined number of revolutions (Rcb), and the first conveyance period (Pt1) has elapsed, the number of revolutions (Rc) per unit time of the rotary classifier 16 is set to the predetermined number of revolutions ( Rcb) or higher.

According to the solid fuel pulverization device 100 according to the present disclosure, since the rotational speed Rc of the rotary classifier 16 does not increase in the first conveyance period Pt1 after the supply of the solid fuel is stopped, now One conveyance period (Pt1) can be used to promote the discharge of the pulverized fuel remaining in the solid fuel pulverizing apparatus 100. Further, after the first conveyance period Pt1 has elapsed, the pulverized fuel accumulated in the rotary classifier 16 can be appropriately removed and discharged to the outside of the rotary classifier 16.

In the solid fuel pulverization apparatus 100 according to the present disclosure, the control unit 50 increases the number of revolutions per unit time of the rotary classifier 16 to a predetermined number of revolutions Rb or more, and then the acceleration period Ps. As this elapses, the number of revolutions Rc per unit time of the rotary classifier 16 is reduced to less than the predetermined number of revolutions Rb.

According to the solid fuel pulverization device 100 according to the present disclosure, the rotational speed Rc of the rotary classifier 16 is maintained at a predetermined rotational speed Rb or more until the acceleration period Ps elapses. After pulverization accumulated in the classifier 16, the fuel can be reliably removed. In addition, since the rotational speed Rc per unit time of the rotary classifier 16 is reduced to less than the predetermined rotational speed Rb, except for the acceleration period Ps, the cost of the rotational power of the rotary classifier 16 can be reduced. have.

The solid fuel pulverization device 100 according to the present disclosure is a differential pressure detection unit 43 that detects a pressure difference between the pressure inside the rotary classifier 16 (SP1) and the pressure outside the rotary classifier 16 (SP2). ), and the controller 50 increases the number of revolutions per unit time of the rotary classifier 16 to a predetermined number of revolutions Rcb or more, and then the differential pressure detected by the differential pressure detection unit 43 becomes equal to or less than the predetermined differential pressure. As a result, the number of revolutions Rc per unit time of the rotary classifier 16 is reduced to less than a predetermined number of revolutions Rcb.

According to the solid fuel pulverization device 100 according to the present disclosure, the differential pressure detection unit 23 detects the differential pressure between the inside (SP1) and the outside (SP2) of the rotary classifier 16, so that the rotary classifier 16 is It is possible to grasp the deposition situation of the fuel after the pulverization that is deposited. Then, as the differential pressure detected by the differential pressure detection unit 43 becomes less than or equal to the predetermined differential pressure, and the pulverized fuel deposited in the interior SP1 decreases, the rotation speed Rc of the rotary classifier 16 is set to the predetermined rotation speed Rcb ) Can be reduced to less than.

In the solid fuel pulverization apparatus 100 according to the present disclosure, the control unit 50 reduces the number of revolutions per unit time of the rotary classifier 16 to less than a predetermined number of revolutions Rcb, and then a second conveyance period. After (Pt2) has elapsed, the rotation of the rotary classifier 16 is stopped.

According to the solid fuel pulverization device 100 according to the present disclosure, since the second conveyance period Pt2 is provided after the acceleration period Ps, this second conveyance period Pt2 is used for the rotary classifier 16. It is possible to promote the discharge of fuel to the outside of the device after pulverization discharged from the inside.

In the solid fuel pulverization apparatus 100 according to the present disclosure, the control unit 50 controls to execute the speed increasing operation a plurality of times in the fuel discharge period Pd.

According to the solid fuel pulverization device 100 according to the present disclosure, since the speed-up operation is performed a plurality of times in the fuel discharge period Pd, the centrifugal force applied to the fuel after pulverization deposited inside the rotary classifier 16 is changed. By increasing the number of times, it is easier to break the bridged state of the fuel after the accumulated pulverization, and it is possible to promote the discharge of the fuel from the inside SP1 to the outside SP2 after the pulverization.

In the solid fuel pulverization device 100 according to the present disclosure, the control unit 50 includes a first control mode for executing a speed increase operation and a unit time of the rotary classifier 16 in the fuel discharge period Pd. It is possible to selectively execute a second control mode in which the number of revolutions Rc is maintained at a constant number of revolutions Rc3.

According to the solid fuel pulverization apparatus 100 according to the present disclosure, a first control mode for executing an increase speed operation and a second control mode for maintaining the rotation speed Rc at a constant rotation speed are selectively selected according to the type of the solid fuel. You can run it.

The power generation plant 1 provided with the solid fuel pulverization device 100 described in each of the embodiments described above is, for example, grasped as follows.

The power generation plant 1 according to the present disclosure includes the solid fuel pulverizing device 100 according to any of the above, a boiler 200 for generating steam by burning solid fuel pulverized in the solid fuel pulverizing device 100, and It includes a power generation unit that generates power using the steam generated by the boiler 200.

According to the power generation plant 1 according to the present disclosure, it is possible to appropriately remove the fuel after pulverization deposited in the rotary classifier without increasing the manufacturing cost of the mill 10 or the weight of the rotary classifier 16. have.

The method of controlling the solid fuel pulverizing device 100 described in each of the embodiments described above is, for example, grasped as follows.

The control method of the solid fuel pulverization device 100 according to the present disclosure includes a rotary table 12 rotating around a rotational central axis while supplying solid fuel from the fuel supply unit 17, and the fuel supply unit 17 to provide solid fuel. A pulverizing roller 13 for pulverizing solid fuel between the fuel feeder 20 and the rotary table 12 for supplying, and a pulverizing roller 13 that rotates around the rotation center axis and is provided at predetermined intervals around the rotation center axis. In the solid fuel pulverization apparatus 100 provided with a plurality of classification blades 16a, and a rotary classifier 16 for classifying fuel after pulverization by pulverization roller 13, the fuel supply unit 20 After stopping the supply of solid fuel by the first stop step (S104) and the fuel discharge period (Pd) after stopping the supply of the solid fuel in the first stop step (S104), the rotary table 12 A second stop step (S110) for stopping rotation and an increase step (S106) for increasing the number of rotations Rc per unit time of the rotary classifier 16 in the fuel discharge period Pd are provided.

According to the control method of the solid fuel pulverization device 100 according to the present disclosure, the fuel discharge period Pd from stopping the supply of the solid fuel by the fuel feeder 20 until the rotation of the rotary table 12 is stopped (Pd ), the number of revolutions Rc of the rotary classifier 16 increases. Because the centrifugal force acting on the fuel after pulverization inside the rotary classifier 16 increases with the increase of the rotational speed Rc of the rotary classifier 16, it breaks the bridge state of the fuel after the accumulated pulverization. , After pulverization, the discharge of fuel from the rotary classifier 16 is promoted. Therefore, it is possible to appropriately remove the fuel after pulverization deposited in the rotary classifier 16 without increasing the manufacturing cost of the mill 10 or the weight of the rotary classifier 16.

1: power plant
10: wheat
11: housing
12: rotary table
13: Roller (crushing roller)
14: drive unit
16: Classifier (rotary classifier)
16a: blade (classification blade)
16b: fixing part
17: fuel supply
18: motor
19: exit
20: feeder (fuel feeder)
22: conveying unit (fuel feeder)
23: motor (fuel feeder)
30: blower (transport gas supply)
30a: thermal gas blower
30b: cold gas blower
30c: thermal gas damper (first air blower)
30d: cold gas damper (second blower part)
40: state detection unit (temperature detection means, differential pressure measurement means)
41: bottom
42: ceiling
43: differential pressure detection unit
50: control unit
100: solid fuel grinding device
100a: primary air flow path (transport gas flow path)
100b: supply euro
200: boiler
210: furnace
220: burner unit (combustion device)
B1: sedimentary assembly fuel
F1: Flow inside the rotary classifier
SP1: Inside (of rotary classifier)
SP2: External (of rotary classifier)
SP3: Space (below the rotary classifier)
Rc: number of revolutions (of rotary classifier)
Rt: number of revolutions (of rotary table)

Claims (9)

A rotary table that rotates around a rotation center axis while solid fuel is supplied from the fuel supply unit,
A fuel supply unit for supplying the solid fuel to the fuel supply unit,
A crushing roller for pulverizing the solid fuel between the rotary table,
A rotary classifier that rotates around the rotation center axis and includes a plurality of classification blades provided at predetermined intervals around the rotation center axis, and classifies the fuel after the solid fuel is pulverized and pulverized,
And a control unit for controlling rotation of the rotary table, supply of the solid fuel by the fuel supplier, and rotation of the rotary classifier,
The control unit temporarily increases the number of revolutions per unit time of the rotary classifier in the fuel discharge period from stopping the supply of the solid fuel by the fuel supplier until the rotation of the rotary table is stopped. A solid fuel pulverizing device that controls to execute an increase speed operation. The method according to claim 1, wherein the control unit makes the rotational speed per unit time of the rotary classifier less than a predetermined rotational speed in a first conveyance period after stopping the supply of the solid fuel by the fuel supplier, and the first After the conveyance period has elapsed, the number of revolutions per unit time of the rotary classifier is increased above the predetermined number of revolutions, and the predetermined number of revolutions is the action of centrifugal force due to the rotation of the fuel after the pulverization inside the rotary classifier. The solid fuel pulverizing apparatus, which is the number of revolutions starting to be discharged from the rotary classifier. The method of claim 2, wherein the control unit increases the number of revolutions per unit time of the rotary classifier to the predetermined number of revolutions or more, and then determines the number of revolutions per unit time of the rotary classifier as an increase period elapses. A solid fuel pulverizing device that reduces to less than a predetermined number of revolutions. The method according to claim 2, further comprising a differential pressure detector configured to detect a pressure difference between an internal pressure of the rotary classifier and an external pressure of the rotary classifier,
The control unit increases the number of revolutions per unit time of the rotary classifier to the predetermined number of revolutions or more, and then the number of revolutions per unit time of the rotary classifier as the differential pressure detected by the differential pressure detection unit becomes less than or equal to a predetermined differential pressure. The solid fuel pulverizing device for reducing the number to less than the predetermined number of revolutions. The method of claim 3 or 4, wherein the control unit reduces the number of revolutions per unit time of the rotary type classifier to less than the predetermined number of revolutions, and then performs rotation of the rotary type classifier after a second conveyance period has elapsed. Solid fuel pulverizing device, which is controlled to stop. The solid fuel pulverizing apparatus according to any one of claims 1 to 4, wherein the control unit controls to execute the speed increasing operation a plurality of times in the fuel discharge period. The method according to any one of claims 1 to 4, wherein the control unit comprises: a first control mode for executing the speed increase operation in the fuel discharge period according to the type of the solid fuel, and of the rotary classifier. A solid fuel pulverizing apparatus capable of selectively executing a second control mode that maintains the number of revolutions per unit time at a constant number of revolutions. The solid fuel pulverizing device according to any one of claims 1 to 4, and
A boiler for generating steam by burning the pulverized solid fuel in the solid fuel pulverizing device,
Power generation unit that generates power using the steam generated by the boiler
With a power plant. A rotary table that rotates around a rotation center axis while solid fuel is supplied from the fuel supply unit,
A fuel supply unit for supplying the solid fuel to the fuel supply unit,
A crushing roller for pulverizing the solid fuel between the rotary table,
A solid fuel pulverizing device having a plurality of classification blades that rotate around the rotational center axis and provided at predetermined intervals around the rotational center axis, and a rotary classifier for classifying fuel after the solid fuel is pulverized and pulverized. Is the control method of,
A first stop step of stopping the supply of the solid fuel by the fuel supplier,
A second stopping step of stopping the rotation of the rotary table after a fuel discharge period has elapsed after stopping the supply of the solid fuel in the first stopping step;
In the fuel discharge period, a control method of a solid fuel pulverizing apparatus comprising a speed-up step of temporarily increasing the number of revolutions per unit time of the rotary classifier.

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