JP2021030114A - Solid fuel pulverization device, power plant and method for controlling solid fuel pulverization device - Google Patents

Abstract

To properly remove a pulverized fuel accumulated inside a rotary classifier without increasing the production cost of a mill and the weight of the rotary classifier.SOLUTION: A solid fuel pulverization device comprises: a rotary table 12 by which a solid fuel is fed from a fuel feeding part 17; a coal feeder feeding the solid fuel to the fuel feeding part 17; a pulverization roller 13 pulverizing the solid fuel with the rotary table 12; a rotary classifier 16 having plural blades 16a and rotating around a rotation center shaft; and a control part controlling rotation of the rotary table 12, feeding of the solid fuel by the coal feeder and rotation of the rotary classifier 16. The control part controls the device to carry out a speed-up operation comprising temporarily increasing a revolution per unit time of the rotary classifier 16 in the fuel discharge period from the stop of feeding the solid fuel by the coal feeder to the stop of rotation of the rotary table 12.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a solid fuel crusher, a power plant, and a method of controlling a solid fuel crusher.

Conventionally, solid fuels (carbon-containing solid fuels) such as coal and biomass fuels are crushed into fine powders smaller than a predetermined particle size by a crusher (mill) and supplied to a combustion apparatus. The mill crushes solid fuel such as coal and biomass fuel charged into the rotary table by chewing it between the rotary table and rollers, and is supplied from the outer circumference of the rotary table via a transport gas flow path. Fuel that has been crushed into fine powder by gas is sorted by a classifier in a predetermined particle size range, transported to a boiler, and burned by a combustion device. In a thermal power plant, steam is generated by heat exchange with the combustion gas generated by burning in a boiler, the steam turbine is rotationally driven by the steam, and the generator connected to the steam turbine is rotationally driven to generate electricity. It is done.

The crushed solid fuel crushed by the mill (the crushed fuel) is classified into fine particles and coarse particles by a rotary classifier installed at the top of the mill. The fine-grained fuel passes between the blades of the rotary classifier and is sent to the combustion device in the subsequent process, and the coarse-grained fuel collides with the blades of the rotary classifier and falls to the rotary table. , Will be crushed again.

As a carbon-containing solid fuel, a wood-based biomass fuel is difficult to be finely crushed, has high flammability, and can be suitably burned even with a relatively large particle size. Therefore, when the biomass fuel is used as the solid fuel, it is usually supplied from the mill to the combustion apparatus provided in the boiler in a state of a particle size about 5 to 10 times larger than that of coal.

As described above, since the particle size supplied to the combustion device differs between coal and biomass fuel, the mill for crushing and classifying solid fuel has a different design for biomass fuel crushing application and coal crushing application (for example, housing shape, etc.). It is inherently preferable to design individually by setting the rotation speed of the rotary table, the rotation speed of the classifier, etc.). However, from the viewpoint of equipment cost and installation space, the same mill can handle both solid fuels of biomass fuel and coal, and a mill that can share the coal and biomass fuel is used. Therefore, it is desired that biomass fuel can be used.

When coal is used as the solid fuel, the particle size after crushing becomes small and uniform (about 100 μm). Therefore, a bridge (a phenomenon in which powders form an arch structure to close a gap) between blades of a rotary classifier is unlikely to occur. Further, since the crushed coal (pulverized coal) has a relatively small angle of repose (about 40 ° to 45 °), it often falls on the rotary 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 size after pulverization is large and non-uniform (about 0.6 mm to 1 mm). Therefore, a bridge may occur between the blades of the rotary classifier. Moreover, since the angle of repose of the crushed biomass fuel is relatively large (about 60 °), it is likely to be deposited inside the rotary classifier.

Further, when biomass fuel is used as the solid fuel, the particle size after crushing 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 made lower than the rotation speed of the rotary classifier when using coal (for example, 90 rpm to 180 rpm). There are times when the emission of crushed biomass fuel is ensured. At this time, when the biomass fuel is used, the centrifugal force acting on the biomass fuel deposited inside the rotary classifier becomes small, and the deposition of the biomass fuel is more likely to proceed. If the crushed biomass fuel is excessively deposited in the rotary classifier, the transport of the crushed biomass fuel to the boiler is hindered. Therefore, it may be necessary to perform cleaning work on a regular basis to remove the biomass fuel accumulated inside the rotary classifier.

To solve the problem of using biomass fuel as solid fuel, a mill equipped with a gas injection mechanism that removes biomass fuel by injecting gas into the biomass fuel deposited inside the rotary classifier has been proposed ( For example, see Patent Document 1).

Japanese Unexamined 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 such circumstances, and appropriately disperses the pulverized fuel deposited inside the rotary classifier without increasing the manufacturing cost of the mill or the weight of the rotary classifier. It is an object of the present invention to provide a solid fuel crushing device capable of removal, a power plant equipped with the solid fuel crushing device, and a control method for the solid fuel crushing device.

The solid fuel crusher according to one aspect of the present disclosure includes a rotary table to which solid fuel is supplied from the fuel supply unit and rotates around the central axis of rotation, and a fuel supply machine that supplies the solid fuel to the fuel supply unit. A crushing roller that crushes the solid fuel between the rotary table and the solid fuel, and a plurality of classification blades that rotate around the rotation center axis and are provided around the rotation center axis at predetermined intervals. It is provided with a rotary classifier for classifying the crushed and crushed fuel, and a control unit for controlling the rotation of the rotary table, the supply of the solid fuel by the fuel supply machine, and the rotation of the rotary classifier. In the fuel discharge period from when the supply of the solid fuel by the fuel supply machine is stopped to when the rotation of the rotary table is stopped, the control unit temporarily determines the number of rotations per unit time of the rotary classifier. Controls to perform a speed-up operation that increases the speed.

The control method of the solid fuel crusher according to one aspect of the present disclosure includes a rotary table in which solid fuel is supplied from the fuel supply unit and rotates around the central axis of rotation, and a fuel for supplying the solid fuel to the fuel supply unit. It is provided with a crushing roller that crushes the solid fuel between the feeder and the rotary table, and a plurality of classification blades that rotate around the rotation center axis and are provided around the rotation center axis at predetermined intervals. In a solid fuel crusher provided with a rotary classifier for classifying the crushed solid fuel after crushing the solid fuel, a first stop step of stopping the supply of the solid fuel by the fuel supply machine and the first stop step. In the second stop step of stopping the rotation of the rotary table after the fuel discharge period has elapsed since the supply of the solid fuel was stopped in the stop step, and in the fuel discharge period, per unit time of the rotary classifier. It is provided with a speed-increasing process for temporarily increasing the number of revolutions.

A solid fuel crusher capable of appropriately removing the crushed fuel accumulated inside the rotary classifier without increasing the manufacturing cost of the mill or the weight of the rotary classifier, and a power plant equipped with the solid fuel crusher. A method for controlling a solid fuel crusher can be provided.

It is a schematic block diagram which showed the power plant which concerns on 1st Embodiment of this disclosure. It is a vertical cross-sectional view which showed the outline of the mill shown in FIG. It is a vertical cross-sectional view which showed around the mounting position of the downstream side detection tube. It is a partially enlarged view of the rotary classifier shown in FIG. It is a figure which shows the relationship between the rotation speed of a rotary classifier and the discharge time of the deposited coarse-grained fuel, and the relationship between the rotation speed of a rotary classifier and the centrifugal force applied to the deposited coarse-grained fuel. It is a flowchart which shows the process which the solid fuel crushing apparatus which concerns on 1st Embodiment of this disclosure performs. It is a flowchart which shows the process which the solid fuel crushing apparatus which concerns on 1st Embodiment of this disclosure performs. It is a flowchart which shows the process which the solid fuel crushing apparatus which concerns on 1st Embodiment of this disclosure performs. It is a graph which showed the change of the fuel supply amount of the coal feeder when the operation of the solid fuel crushing apparatus which concerns on 1st Embodiment is stopped. It is a graph which showed the change of the rotation speed per unit time of the rotary classifier when the operation of the solid fuel crushing apparatus which concerns on 1st Embodiment is stopped. It is a graph which showed the change of the rotation speed per unit time of the rotary table when the operation of the solid fuel crushing apparatus which concerns on 1st Embodiment is stopped. It is a graph which showed the change of the flow rate of the primary air supplied to the mill when the operation of the solid fuel crushing apparatus which concerns on 1st Embodiment is stopped. It is a graph which showed the change of the fuel amount on the rotary table when the operation of the solid fuel crushing apparatus which concerns on 1st Embodiment is stopped. It is a graph which showed the change of the rotation speed per unit time of the rotary classifier when the operation of the solid fuel crushing apparatus which concerns on 2nd Embodiment is stopped. It is a graph which showed the change of the fuel amount on the rotary table when the operation of the solid fuel crushing apparatus which concerns on 2nd Embodiment is stopped.

[First Embodiment]
Hereinafter, the first embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a power plant 1 according to the first embodiment of the present disclosure. FIG. 2 is a vertical cross-sectional view showing an outline of the mill 10 shown in FIG.

<Overall configuration of power plant 1>
The power plant 1 according to the present embodiment includes a solid fuel crusher 100 and a boiler 200.
The solid fuel crushing device 100 is, for example, a device that crushes a solid fuel (carbon-containing solid fuel) such as coal or biomass fuel to generate fine-grained fuel and supplies it to the burner section (combustion device) 220 of the boiler 200. The power plant 1 including the solid fuel crushing device 100 and the boiler 200 shown in FIG. 1 includes one solid fuel crushing device 100, and corresponds to each of the plurality of burner portions 220 of the one boiler 200. The system may be provided with a plurality of solid fuel crushing devices 100.

The solid fuel crushing device 100 of the present embodiment includes a mill (crushing unit) 10, a coal feeder (fuel supply machine) 20, a blower unit (transport gas supply unit) 30, a state detection unit 40, and a control unit. (Determination unit) 50 is provided.
In the present embodiment, "upper" means the direction of the vertically upper side, and "upper" such as the upper part and the upper surface means the part on the vertically upper side. Similarly, "bottom" indicates the part on the vertically lower side.

The mill 10 for crushing solid fuel such as coal or biomass fuel supplied to the boiler 200 into fine pulverized fuel which is a pulverized solid fuel may be in the form of crushing only coal or crushing only biomass fuel. It may be in the form of crushing biomass fuel together with coal.
Here, the biomass fuel is a renewable organic resource derived from living organisms, for example, thinned wood, waste wood, drifting wood, grass, waste, sludge, tires, and recycled fuel (pellets and pellets) made from these. Chips), etc., and are not limited to those presented here. Since biomass fuel takes in carbon dioxide during the growth process of biomass, it is considered to be carbon-neutral, which does not emit carbon dioxide, which is a global warming gas, and its use is being 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 a motor 18 that rotationally drives the rotary classifier 16. And have.
The housing 11 is formed in a tubular shape extending in the vertical direction, and is a housing that houses a rotary table 12, a roller 13, a rotary classifier 16, and a fuel supply unit 17. A fuel supply unit 17 is attached to the central portion of the ceiling portion 42 of the housing 11. The fuel supply unit 17 supplies the solid fuel guided 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 portion extends to the inside of the housing 11. ..

A drive unit 14 is installed near the bottom surface portion 41 of the housing 11, and a rotary table 12 that rotates by a driving force transmitted from the drive unit 14 is rotatably arranged.
The rotary table 12 is a member having a circular shape in a plan view, and is arranged so that the lower ends of the fuel supply unit 17 face each other. The upper surface of the rotary table 12 may have an inclined shape such that the central portion is low and the rotary table 12 is high toward the outside, and the outer peripheral portion may be bent upward. The fuel supply unit 17 supplies solid fuel (for example, coal or biomass fuel in this embodiment) from the upper side to the lower rotary table 12, and the rotary table 12 crushes the supplied solid fuel with the roller 13. It is also called a crushing table.

When the solid fuel is charged from the fuel supply unit 17 toward the center of the rotary table 12, the solid fuel is guided to the outer peripheral side of the rotary table 12 by the centrifugal force due to the rotation of the rotary table 12, and is between the solid fuel and the roller 13. It is sandwiched and crushed. The crushed solid fuel (fuel after crushing) is moved upward by the transport gas (hereinafter referred to as primary air) guided from the transport gas flow path (hereinafter referred to as primary air flow path) 100a. Is blown up and led to the rotary classifier 16.

That is, an outlet (not shown) is provided on the outer periphery of the rotary table 12 to allow the primary air flowing in from the primary air flow path 100a to flow out into the space above the rotary table 12 in the housing 11. A vane (not shown) is installed at the air outlet to give a turning force to the primary air blown out from the air outlet. The primary air to which the swirling force is applied by the vane becomes an air flow having a swirling velocity component, and guides the solid fuel crushed on the rotary table 12 to the upper rotary classifier 16 in the housing 11. Of the crushed solid fuel mixed in the primary air, those having a particle size larger than the predetermined particle size are classified by the rotary classifier 16 or fall without reaching the rotary classifier 16 and fall on the rotary table. It is returned to 12 and crushed again.

The roller 13 is a rotating body that crushes 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 crush the solid fuel. In FIG. 1, only one roller 13 is represented 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. To. For example, the three rollers 13 are arranged at equal intervals in the circumferential direction with an angular interval of 120 ° on the outer peripheral portion. In this case, the portion where the three rollers 13 are in contact with the upper surface of the rotary table 12 (the portion to be pressed) is equidistant from the rotation center axis of the rotary table 12.

The roller 13 can be swung up and down by the journal head 45, and is supported so as to be close to and separated 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 around the roller 13. When the solid fuel is supplied from the fuel supply unit 17, the solid fuel is pressed between the roller 13 and the rotary table 12 and crushed to become fine fuel.

The support arm 47 of the journal head 45 is supported on the side surface of the housing 11 by a support shaft 48 whose intermediate portion is along the horizontal direction so as to be swingable in the vertical direction of the rollers about the support shaft 48. Further, a pressing device 49 is provided at the upper end portion on the vertically upper side of the support arm 47. The pressing device 49 is fixed to the housing 11 and applies a load to the roller 13 via the 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 to rotate the rotary table 12 around a central axis. The drive unit 14 generates a driving force for rotating 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 outer shape. The rotary classifier 16 includes a plurality of blades 16a extending in the vertical direction at its outer peripheral position. The blades 16a are provided at predetermined intervals (equal intervals) around the central axis of the rotary classifier 16. Further, the rotary classifier 16 uses a solid fuel crushed by the roller 13 having a size larger than a predetermined particle size (for example, 70 to 100 μm for coal) (hereinafter, crushed solid fuel exceeding a predetermined particle size as “coarse powder”. It is a device that classifies fuel into (referred to as "fuel") and fuel having a predetermined particle size or less (hereinafter, crushed solid fuel having a predetermined particle size or less is referred to as "fine powder fuel"). The rotary classifier 16 that classifies by rotation is also called a rotary separator, and is given a rotational driving force by a motor 18 controlled by a control unit 50 to provide a cylindrical shaft (not shown) extending in the vertical direction of the housing 11. It rotates around the fuel supply unit 17 in the center.

The crushed solid fuel that has reached the rotary classifier 16 has a relative balance between the centrifugal force generated by the rotation of the blade 16a and the centripetal force due to the airflow of the primary air. It is knocked down, returned to the turntable 12, crushed again, and the pulverized fuel is guided to an outlet 19 at the ceiling 42 of the housing 11.
The pulverized fuel classified by the rotary classifier 16 is discharged from the outlet 19 to the supply flow path 100b, and is conveyed to the subsequent process together with the primary air. The pulverized fuel that has flowed out to the supply flow path 100b is supplied to the burner portion 220 of the boiler 200.

The fuel supply unit 17 is attached so that the lower end portion extends vertically to the inside of the housing 11 so as to penetrate the upper end of the housing 11, and the solid fuel input from the upper part of the fuel supply unit 17 is transferred to the rotary table 12. Supply to the approximately central region of. The fuel supply unit 17 is supplied with solid fuel from the coal feeder 20.

The coal feeder 20 includes a transport unit 22 and a motor 23. The transport unit 22 transports the solid fuel discharged from the lower end portion of the down spout portion 24 directly under the bunker 21 by the driving force given from the motor 23, and is guided to the fuel supply unit 17 of the mill 10. Normally, primary air for transporting pulverized fuel, which is a crushed solid fuel, is supplied to the inside of the mill 10, and the pressure is increased. Fuel is held in a laminated state inside the down spout portion 24, which is a pipe extending in the vertical direction directly under the bunker 21, and the solid fuel layer laminated in the down spout portion 24 causes the mill 10 side. The sealing property is ensured so that the primary air and fine fuel do not flow back. The amount of solid fuel supplied to the mill 10 may be adjusted by the belt speed of the belt conveyor of the transport unit 22.

On the other hand, the biomass fuel chips and pellets before crushing have a constant particle size (the size of the pellets) as compared with coal fuel (that is, the particle size of coal before crushing is, for example, about 2 to 50 mm). Is, for example, about 6 to 8 mm in diameter and about 40 mm or less in length), and is lightweight. Therefore, when the biomass fuel is stored in the down spout portion 24, the gap formed between the biomass fuels becomes larger than that in the case of the coal fuel.

Therefore, since there is a gap between the biomass fuel chips and pellets in the down spout portion 24, the primary air blown up from the inside of the mill 10 and the fine powder fuel pass through the gap formed between the biomass fuels and the mill. 10 The internal pressure may drop. Further, when the primary air blows into the storage portion of the bunker 21, the transportability of the biomass fuel deteriorates and dust is generated, the bunker 21 and the down spout portion 24 are ignited, and when the pressure inside the mill 10 decreases, the pulverized fuel There is a possibility that various problems may occur in the operation of the mill 10, such as a decrease in the amount of fuel transported. Therefore, a rotary valve (not shown) may be provided in the middle of the fuel supply unit 17 from the coal feeder 20 to suppress the backflow due to the blow-up of the primary air and the pulverized fuel.

The blower unit 30 is a device that dries the solid fuel crushed by the roller 13 and blows primary air into the housing 11 for supplying the rotary classifier 16. The blower unit 30 includes a hot gas blower 30a, a cold gas blower 30b, a hot gas damper 30c, and a cold gas damper 30d in order to adjust the primary air blown to the housing 11 to an appropriate temperature.

The hot gas blower 30a is a blower that blows the heated primary air supplied from a heat exchanger (heater) such as an air preheater. A hot gas damper 30c (first blower portion) is provided on the downstream side of the hot gas blower 30a. The opening degree of the heat 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 opening degree of the hot gas damper 30c.

The cold gas blower 30b is a blower that blows primary air that 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 opening degree 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 by the opening degree of the cold gas damper 30d.

The flow rate of the primary air is the total 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 is the primary air blown by the hot gas blower 30a. Is determined by the mixing ratio of the primary air blown by the cold gas blower 30b, and is controlled by the control unit 50.
Further, a part of the combustion gas discharged from the boiler 200 is guided to the primary air blown by the hot gas blower 30a via a gas recirculation ventilator (not shown) to form an air-fuel mixture from the primary air flow path 100a. The oxygen concentration of the inflowing primary air may be adjusted.

In the present embodiment, the state detection unit 40 of the housing 11 transmits the measured or detected data to the control unit 50. The state detection unit 40 of the present embodiment is, for example, a differential pressure measuring means, and is a portion where the primary air flows from the primary air flow path 100a into the inside of the mill 10 and the primary air and fine powder fuel from the inside of the mill 10 into the supply flow path 100b. The differential pressure with the outlet 19 discharged from the mill 10 is measured as the differential pressure in the mill 10. For example, depending on the classification performance of the rotary classifier 16, the increase / decrease in the circulation amount of the crushed solid fuel that circulates inside the mill 10 between the vicinity of the rotary classifier 16 and the vicinity of the rotary table 12 and the difference in the mill 10 with respect to this. The increase and decrease of pressure changes. That is, since the pulverized fuel discharged from the outlet 19 can be adjusted and managed with respect to the solid fuel supplied to the inside of the mill 10, the particle size of the pulverized fuel does not affect the combustibility of the burner portion 220. A large amount of pulverized fuel can be supplied to the burner portion 220 provided in the boiler 200.

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

The control unit 50 is a device that controls each part of the solid fuel crushing device 100. The control unit 50 may control the rotation speed of the rotary table 12 with respect to the operation of the mill 10 by transmitting a drive instruction to the drive unit 14, for example. The control unit 50 optimizes the differential pressure in the mill 10 within a predetermined range by adjusting the classification performance by, for example, transmitting a drive instruction to the motor 18 of the rotary classifier 16 to control the rotation speed. It is possible to stabilize the supply of pulverized fuel. Further, the control unit 50 adjusts the supply amount of the solid fuel that the transport unit 22 conveys the solid fuel and supplies it to the fuel supply unit 17 by transmitting a drive instruction to the motor 23 of the coal feeder 20, for example. Can be done. Further, the control unit 50 can control the opening degree of the hot gas damper 30c and the cold gas damper 30d to control the flow rate and temperature of the primary air by transmitting the opening degree instruction to the blower unit 30.

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. Then, as an example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is installed in a ROM or other storage medium in advance, is provided in a state of being stored in a computer-readable storage medium, or is distributed via a wired or wireless communication means. Etc. may be applied. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like.

Next, the boiler 200 that burns using the fine fuel supplied from the solid fuel crusher 100 to generate steam will be described.
The boiler 200 includes a fireplace 210 and a burner section 220.

The burner unit 220 is a device for forming a flame by burning the pulverized fuel using the primary air containing the pulverized fuel supplied from the supply flow path 100b and the secondary air supplied from the heat exchanger (not shown). Is. The pulverized fuel is burned 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 by an environmental device (not shown by a denitration device, an electrostatic precipitator, etc.), and heat exchange with the outside air is performed by a heat exchanger such as an air preheater (not shown). It is carried out and guided to a chimney (not shown) via an attractant ventilator (not shown) and released into the atmosphere. The outside air heated by heat exchange with the combustion gas in the heat exchanger is sent to the heat gas blower 30a described above.

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 to generate power. It is sent to a steam turbine (not shown), which is a unit, to rotate drive the steam turbine, and a generator connected to the steam turbine (not shown) is driven to rotate to generate power.

<Differential pressure detector>
FIG. 2 shows a differential pressure detecting unit 43 provided separately from the state detecting unit 40. The differential pressure detection unit 43 detects a differential pressure different from the mill differential pressure, which is the differential pressure between the upstream side (inside 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 includes the pressure of the internal SP1 of the rotary classifier 16 on the inner peripheral side of the blade 16a and the outer peripheral side of the blade 16a and the inside of the housing 11 (outside of the rotary classifier 16). The differential pressure from the pressure of SP2) (hereinafter, this differential pressure is referred to as "classifier differential pressure") is measured.

More specifically, the differential pressure detection unit 43 measures the differential pressure between the upstream side (external SP2) and the downstream side (internal SP1) in the flow of the primary air (transport gas) containing fuel after crushing the blade 16a. .. As the differential pressure detecting unit 43, for example, a digital manometer 43a is used. The measured value of the manometer 43a is transmitted to the control unit 50. The differential pressure detection unit 43 is not limited to a differential pressure gauge such as a digital manometer, and may be a differential pressure gauge of another type, and is upstream and downstream in the primary air flow including fuel after crushing the blade 16a. A pressure gauge may be provided for each of the pressure gauges to obtain the difference between the pressure values measured by these pressure gauges.

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

As shown in FIG. 2, in the present embodiment, the lower end of each blade 16a is fixed by the fixing portion 16b. At the bottom of the rotary classifier 16 including the fixed portion 16b, a plurality of fixed portions 16b are provided with respect to the space SP3 vertically below the rotary classifier 16, and are usually not classified by the blade 16a. Even if there is coarse-grained fuel (coarse-grained fuel) that has entered the internal SP1 of the rotary classifier 16, it falls into the rotary table 12 through the gaps between the plurality of fixed portions 16b and is discharged from the SP1.

On the other hand, there is a case where the crushed fuel that has entered the internal SP1 of the rotary classifier 16 without being sufficiently crushed is deposited as the deposited coarse-grained fuel B1 on the upper side from the plurality of fixed portions 16b. When a bridge is generated in the deposited coarse-grained fuel B1 to close the gap between the plurality of fixed portions 16b, the accumulated coarse-grained fuel B1 increases the accumulated amount from the lower side to the upper side of each blade 16a, and the blades. Since the effective area for classification of 16a is blocked, the classification performance of the rotary classifier 16 deteriorates. Further, when the deposited amount of the deposited coarse-grained fuel B1 increases from the lower side to the upper side of the blade 16a, 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 internal SP1 and the external SP2 of the rotary classifier 16 obtained by the differential pressure detecting unit 43.

FIG. 3 shows the opening side end portion of the downstream side detection tube 43c. In the present embodiment, the downstream detection tube 43c is inserted into the internal SP1 of the rotary classifier 16 through the opening 42a formed in the ceiling portion 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 inserted via an O-ring 44. Although the state before fixing the flange portion 46 is shown in FIG. 3, when fixing the flange portion 46, the flange portion 46 is fixed by a fixing bolt (not shown). In this way, the downstream side detection tube 43c can be easily removed by using the flange portion 46. Therefore, when it is not necessary to measure the pressure of the internal SP1 of the rotary classifier 16, the downstream side detection pipe 43c may be removed, and the downstream side detection pipe 43c can be prevented from being blocked by fuel after crushing.

The downstream side detection tube 43c may be bent so that the open end 43c1 at the tip thereof intersects the upstream side direction of the internal flow F1 toward the outlet 19. In the present embodiment, the internal SP1 is curved in an L shape, and the opening end 43c1 at the tip is provided so as to face the outlet 19 side which is the downstream side direction of the internal flow F1. As a result, the static pressure can be accurately measured by reducing the influence of the dynamic pressure of the flow F1 inside the rotary classifier 16. The direction of the opening end 43c1 may be any direction as long as the influence of the dynamic pressure of the flow F1 inside the rotary classifier 16 can be ignored. In this case, for example, the tip of the downstream detection tube 43c may be a straight tube facing vertically downward.

As shown in FIG. 3, the 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. Purge air (purge fluid) can flow from the purge pipe 43e toward the open end 43c1 of the downstream detection pipe 43c. As a result, it is possible to prevent the downstream side detection pipe 43c from being blocked by the crushed fuel contained in the flow F1 inside the classifier that invades from the open end 43c1. Therefore, the purge air is not normally supplied, but is supplied when a blockage of the downstream detection pipe 43c is detected. In addition, purge air may be supplied regularly. As the purging fluid, an inert gas such as nitrogen may be used instead of air.

<Deposition of coarse-grained fuel B1>
FIG. 4 is a partially enlarged view of the rotary classifier 16 shown in FIG. As shown in FIG. 4, in the internal SP1 of the rotary classifier 16, for example, a situation in which the deposited coarse-grained fuel B1 is deposited on the upper side of the fixed portion 16b is schematically illustrated. FIG. 4 shows a state in which the amount of deposit increases from the lower side to the upper side of each blade 16a and a part of the effective area for classification of the blade 16a is closed (hereinafter, also referred to as a bridge state). The rotation center axis X shown in FIG. 4 is an axis that is the center of rotation of the rotary classifier 16 and extends along the vertical direction.

The deposited coarse-grained fuel B1 shown in FIG. 4 is, for example, one in which coarse-grained fuel obtained by crushing a biomass fuel is deposited. The angle of repose of the deposited coarse-grained fuel B1 is larger than the angle θ formed by the upper surface of the fixed portion 16b with the horizontal plane (for example, about 60 °). Therefore, when the deposited coarse-grained fuel B1 is deposited on the upper surface of the fixed portion 16b and a bridge is generated, it is likely to be deposited on the internal SP1 of the rotary classifier 16. In the bridge state shown in FIG. 4, the effective area for classifying the blade 16a is blocked, so that the classifying performance of the rotary classifying machine 16 deteriorates.

The inventors have deposited the number of revolutions Rc [rpm] per unit time of the rotary classifier 16 in the rotary classifier 16 in which the deposited coarse-grained fuel B1 in the bridge state shown in FIG. 4 is deposited on the internal SP1. The relationship with the time required to discharge the coarse-grained fuel B1 from the internal SP1 of the rotary classifier 16 to the external SP2 (hereinafter, also referred to as discharge time) was investigated. In addition, the relationship between the rotation speed Rc [rpm] per unit time of the rotary classifier 16 and the centrifugal force applied to the deposited coarse-grained fuel B1 was investigated.

FIG. 5 shows the relationship between the rotation speed Rc [rpm] per unit time of the rotary classifier 16 and the discharge time of the deposited coarse-grained fuel B1, and the rotation speed Rc [rpm] per unit time of the rotary classifier 16. It is a figure which shows the relationship of the centrifugal force applied to the deposited coarse grain fuel B1.

In FIG. 5, Rcmax indicates the maximum rotation speed of the rotary classifier 16 driven by the motor 18. Rc1 indicates the rotation speed of the rotary classifier 16 in the normal operation operation when crushing the biomass fuel. Rc1 is set to, for example, a value of 5% to 30% of Rcmax. Rc2 is a value of the number of revolutions at which the deposited coarse-grained fuel B1 is effectively discharged from the internal SP1 of the rotary classifier 16 to the external SP2, and is a rotary type in the speed-up operation described later when the biomass fuel is crushed. The rotation speed of the classifier 16 is shown. Rcb is a predetermined rotation speed indicating the rotation speed of the rotary classifier 16 when the deposited coarse-grained fuel B1 in the bridge state starts to be discharged from the internal SP1 to the external SP2 by the action of centrifugal force. Fb indicates the centrifugal force applied to the deposited coarse-grained fuel B1 when the rotary classifier 16 rotates at a predetermined rotation speed Rcb.

As shown in FIG. 5, when the rotation speed of the rotary classifier 16 is lower than the predetermined rotation speed Rcb, the centrifugal force applied to the deposited coarse-grained fuel B1 is smaller than Fb. In this case, since the centrifugal force applied to the deposited coarse-grained fuel B1 is too small, the bridged state of the deposited coarse-grained fuel B1 is maintained, and the deposited coarse-grained fuel B1 is not discharged to the outside SP2. On the other hand, when the rotation speed of the rotary classifier 16 becomes larger than the predetermined rotation speed Rcb, the centrifugal force gradually increases more than Fb, and the discharge time of the deposited coarse-grained fuel B1 gradually shortens. This is because the bridge state of the deposited coarse-grained fuel B1 begins to collapse due to the action of centrifugal force, and the deposited coarse-grained fuel B1 begins to be discharged from the internal SP1 to the external SP2.

From the above investigation results, the inventors set the rotation speed of the rotary classifier 16 to be higher than the predetermined rotation speed Rcb, so that the bridge state of the deposited coarse-grained fuel B1 began to collapse and was discharged from the internal SP1 to the external SP2. I got the knowledge to start. On the other hand, when the rotation speed of the rotary classifier 16 is higher than Rc1 which is the rotation speed in the normal operation operation, the inflow amount of the solid fuel crushed by the contact with the blade 16a from the external SP2 to the internal SP1 is reduced. It is known. Therefore, the inventors have suppressed the influence of increasing the rotation speed of the rotary classifier 16 to be higher than Rc1 which is the rotation speed in the normal operation operation, and break the bridge state of the deposited coarse-grained fuel B1 to break the deposited coarse-grained fuel B1. A control method for appropriately discharging the fuel B1 from the internal SP1 to the external SP2 has been devised.

Hereinafter, the control method of the solid fuel crusher 100 of the present embodiment will be described with reference to the drawings. 6, FIG. 7, and FIG. 8 are flowcharts showing the processes executed by the solid fuel crusher 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 crushing device 100, and is performed by the control unit 50 included in the solid fuel crushing device 100 executing a control program.

FIG. 9 is a graph showing a change in the fuel supply amount of the coal feeder 20 when the operation of the solid fuel crusher 100 is stopped. FIG. 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 crusher 100 is stopped. FIG. 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 crushing apparatus 100 is stopped. FIG. 12 is a graph showing a change in the flow rate of the primary air supplied to the mill 10 when the operation of the solid fuel crushing device 100 is stopped. FIG. 13 is a graph showing changes in the amount of solid fuel loaded on the rotary table 12 when the operation of the solid fuel crusher 100 is stopped.

In FIGS. 9 to 13, the time T1 is the time when the supply of solid fuel to the mill 10 by the coal feeder 20 is stopped. The time T2 is the time at which the classifier speed-up operation of the rotary classifier 16 is performed. The time T3 is the time at which the classifier deceleration operation of the rotary classifier 16 is performed. Time T4 is a time when the rotation of the rotary classifier 16, the rotation of the rotary table 12, and the supply of the primary air to the mill 10 are stopped. As shown in FIG. 10, the period from time T1 to time T4 is the fuel discharge period Pd, Pd ′ that discharges the crushed fuel that stays inside the mill 10 to the outside when the operation of the solid fuel crushing device 100 is stopped. It becomes. The fuel discharge periods Pd and Pd'are set to, for example, 10 minutes to 30 minutes in this embodiment.

The solid fuel crushing device 100 of the present embodiment can use coal or biomass fuel as the solid fuel to be crushed. The solid fuel crusher 100 can execute a control mode according to the type of fuel depending on whether coal is used or biomass fuel is used. Hereinafter, the control mode executed by the solid fuel crusher 100 when biomass fuel is used is referred to as the first control mode, and the control mode executed by the solid fuel crusher 100 when coal is used is referred to as the second control mode.

The solid fuel crushing device 100 includes an operating device (not shown) for receiving a control mode selection instruction from the operator. The control unit 50 of the solid fuel crushing device 100 selects the first control mode or the second control mode according to an instruction from a control device (not shown) of the power plant 1 or an instruction received from the operator via the operation device. To execute.

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 in the first control mode (whether in the second control mode). When the control unit 50 determines that the instruction of the first control mode is being accepted, the process proceeds to step S102, and when it is determined that the instruction of the first control mode is not accepted, the control unit 50 issues an instruction of the second control mode. It is determined that the acceptance is accepted, and the process proceeds to step S111 shown in FIG. The process executed in steps S102 to S110 is the process of the first control mode. The process executed in steps S111 to S115 is the process of the second control mode.

First, the first control mode executed in steps S102 to S110 will be described.
In step S102, the control unit 50 controls to execute the first operation operation. The first operation operation is the operation of the normal operation in the first control mode in which the biomass fuel is used as the solid fuel. In the first operation operation, the control unit 50 sets the coal feeder 20 so that the fuel supply amount of the biomass fuel supplied by the coal feeder 20 becomes Wf1 shown in FIG. 9 according to the load required by the boiler 200 and the like. Control.

Further, in the first operation operation, the control unit 50 controls the motor 18 so that the rotation speed Rc per unit time of the rotary classifier 16 becomes Rc1 shown in FIG. 10 suitable for crushing the biomass fuel. Further, the control unit 50 controls the drive unit 14 so that the rotation speed Rt per unit time of the rotary table 12 becomes Rt1 shown in FIG. 11 in the first operation operation. Further, in the first operation operation, the control unit 50 blows the air unit 30 so that the flow rate of the primary air supplied to the mill 10 becomes V1 shown in FIG. 12 according to the load required by the boiler 200 and the like. To control.

In step S103, the control unit 50 determines whether or not an instruction from a control device (not shown) of the power plant 1 or an operation stop instruction is received from the operator via the operation device, or whether or not a predetermined operation stop condition is satisfied. judge. If the determination result is YES, the control unit 50 proceeds to step S104, and if the determination result is NO, repeats step S103.

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

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

In step S106 (speed increasing step), the control unit 50 executes a classifying machine speed increasing operation for increasing the rotation speed Rc of the rotary classifying machine 16 at the time T2 when the first transport period Pt1 has elapsed from the time T1. When step S106 is executed, as shown in FIG. 10, the rotation speed Rc of the rotary classifier 16 increases from Rc1 during normal operation to Rc2.

Rc2 is a rotation speed equal to or higher than the predetermined rotation speed Rcb shown in FIG. 5, and is more preferably a rotation speed at which the deposited coarse-grained fuel B1 is effectively discharged from the internal SP1 of the rotary classifier 16 to the external SP2. .. Rcb is the rotation speed of the rotary classifier 16 when the deposited coarse-grained fuel B1 in the bridge state starts to be discharged from the internal SP1 to the external SP2 by the action of centrifugal force. Since Rc2 has a rotation speed equal to or higher than Rcb, the deposited coarse-grained fuel B1 in the bridge state can be reliably destroyed. 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 that gradually increases the amount of biomass fuel on the rotary table 12 is that the deposited coarse-grained fuel B1 is discharged from the rotary classifier 16 to the rotary table 12. Another factor that causes the amount of biomass fuel on the rotary table 12 to gradually increase is that the rotation speed Rc of the rotary classifier 16 increases from Rc1 to Rc2 during normal operation during the acceleration period Ps. This is because it is difficult for fuel to flow into the internal SP1 from the external SP2 of the formula classifier 16 after crushing.

In step S107, the control unit 50 determines whether or not the predetermined acceleration period Ps has elapsed from the time T2. If YES, the process proceeds to step S108, and if NO, the determination in step S107 is performed again. The speed-increasing period Ps is a period set in advance so that the deposited coarse-grained fuel B1 of the internal SP1 of the rotary classifier 16 is completely discharged to the external SP2. In the present embodiment, the acceleration period Ps is set to, for example, a predetermined period of 1/3 as the fuel discharge period Pd.

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 the time T3 when the acceleration period Ps elapses from the time T2. When step S108 is executed, as shown in FIG. 10, the rotation speed Rc of the rotary classifier 16 decreases from Rc2 during the speed-increasing operation to, for example, Rc1 during the normal operation. The rotation speed Rc of the rotary classifier 16 in the classifier deceleration operation decreases from Rc2, but may be higher than Rc1 during normal operation.

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

One of the factors that gradually decreases the amount of biomass fuel on the rotary table 12 is that the biomass fuel on the rotary table 12 that has increased during the acceleration period Ps is crushed and once flows into the internal SP1 of the rotary classifier 16. This is because it was discharged to the external SP2. That is, since it is a biomass fuel after crushing, it is not necessary to provide a crushing time, and the fuel can be guided from the external SP2 of the rotary classifier 16 to the internal SP1 in a short time. Another factor that causes the amount of biomass fuel on the rotary table 12 to gradually decrease is that the crushed biomass fuel that has fallen on the rotary table 12 is further finely crushed during the acceleration period Ps.

In step S110 (second stop step), the control unit 50 stops the operation of the solid fuel crushing device 100 because the fuel discharge period Pd has ended at the time T4 when the second transport period Pt2 has elapsed from the time T3. To execute. The control unit 50 controls the motor 18 so as to stop the rotation of the rotary classifier 16 in the stop operation. Further, the control unit 50 controls the drive unit 14 so as to stop the rotation of the rotary table 12 in the stop operation.

Further, the control unit 50 controls the blower unit 30 so as to stop the supply of the primary air to the mill 10 by the blower unit 30 in the stop operation. It is not always necessary to stop the supply of primary air. For example, when there is a request for primary air supply from the boiler 200, or when purging the volatile matter generated in the mill 10, cooling air is supplied to the burner section 220. In some cases, the blower portion 30 may be controlled so as to continue the supply of the primary air. After executing step S110, the control unit 50 ends the control of the solid fuel crushing device 100 by 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 the solid fuel, and is a mode in which the rotation speed Rc of the rotary classifier 16 is maintained at a constant rotation speed Rc3 during the fuel discharge period Pd. Rc3 is set to, for example, a value of 60% to 90% of Rcmax, which is the maximum rotation speed of the rotary classifier 16.

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

Further, the control unit 50 controls the motor 18 so that the rotation speed Rc per unit time of the rotary classifier 16 becomes Rc3 shown in FIG. 10 suitable for crushing coal in the second operation operation. 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 size of the biomass fuel after crushing is larger than that of coal, and it is difficult for the biomass fuel to pass through the rotary classifier 16.

Further, the control unit 50 controls the drive unit 14 so that the rotation speed Rt per unit time of the rotary table 12 becomes Rt2 shown in FIG. 11 in the second operation operation. The rotation speed Rt2 per unit time of the rotary table 12 may be the same as Rt1. Further, in the second operation operation, the control unit 50 blows the air unit 30 so that the flow rate of the primary air supplied to the mill 10 becomes V2 shown in FIG. 12 according to the load required by the boiler 200 and the like. To control. The flow rate V2 of the primary air may be the same as V1.

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

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

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

In step S115, the control unit 50 executes a stop operation for stopping the operation of the solid fuel crushing device 100 at the time T4'when the fuel discharge period Pd'elapses from the time T1. The control unit 50 controls the motor 18 so as to stop the rotation of the rotary classifier 16 in the stop operation. Further, the control unit 50 controls the drive unit 14 so as to stop the rotation of the rotary table 12 in the stop operation. Further, the control unit 50 controls the blower unit 30 so as to stop the supply of the primary air to the mill 10 by the blower unit 30 in the stop operation.

It is not always necessary to stop the supply of primary air. For example, when there is a request for primary air supply from the boiler 200, or when purging the volatile matter generated in the mill 10, cooling air is supplied to the burner section 220. In some cases, the blower portion 30 may be controlled so as to continue the supply of the primary air. After executing step S115, the control unit 50 ends the control of the solid fuel crushing device 100 by the second control mode.

The actions and effects of the solid fuel crusher 100 of the present embodiment described above will be described.
According to the solid fuel crusher 100 of the present embodiment, the fuel discharge period Pd from when the type of solid fuel is determined and the supply of solid fuel by the coal feeder 20 is stopped until the rotation of the rotary table 12 is stopped. In, the rotation speed Rc of the rotary classifier 16 can be increased. When the accumulated coarse-grained fuel B1 (fuel after crushing) is deposited in the internal SP1 of the rotary classifier 16, for example, when the solid fuel is a biomass fuel, the rotation speed Rc of the rotary classifier 16 increases. Since the centrifugal force acting on the deposited coarse-grained fuel B1 (fuel after crushing) of the internal SP1 of the rotary classifier 16 increases, the discharge of the deposited coarse-grained fuel B1 from the rotary classifier 16 is promoted. Therefore, the deposited coarse-grained fuel B1 deposited on the internal SP1 of the rotary classifier 16 can be appropriately removed without increasing the manufacturing cost of the mill 10 and the weight of the rotary classifier 16.

Further, according to the solid fuel crusher 100 according to the present disclosure, the rotation speed Rc of the rotary classifier 16 is not increased in the predetermined first transport period Pt1 after the supply of the solid fuel is stopped. The transport period Pt1 can be used to promote the discharge of the deposited coarse-grained fuel B1 retained in the internal SP1 of the rotary classifier 16. Further, after the predetermined first transport period Pt1 has elapsed, the deposited coarse-grained fuel B1 deposited on the internal SP1 of the rotary classifier 16 can be appropriately removed and discharged to the external SP2.

Further, according to the solid fuel crushing apparatus 100 according to the present disclosure, the rotation speed Rc of the rotary classifier 16 is a predetermined rotation speed Rcb (deposition in a bridge state due to the action of centrifugal force) until a predetermined acceleration period Ps elapses. Since the coarse-grained fuel B1 is maintained above the rotation speed of the rotary classifier 16 when it starts to be discharged from the internal SP1 to the external SP2), the deposited coarse-grained fuel B1 deposited on the internal SP1 of the rotary classifier 16 is ensured. Can be removed.
Further, according to the solid fuel crushing apparatus 100 according to the present disclosure, since a predetermined second transport period Pt2 is provided after the predetermined acceleration period Ps, the rotary classifier 16 uses the second transport period Pt2. The crushed fuel discharged from the inside of the device can be discharged from the outlet 19 to the supply flow path 100b to promote the discharge to the outside of the device.

[Second Embodiment]
Next, the second embodiment of the present disclosure will be described with reference to the drawings. This embodiment is a modification of the first embodiment, and is the same as that of the first embodiment except for the cases described below, and the description thereof will be omitted below.

When the solid fuel crusher 100 of the first embodiment executes the first control mode using biomass fuel, the classifier speed-up operation for increasing the rotation speed Rc of the rotary classifier 16 during the fuel discharge period Pd. Was executed only once. On the other hand, the solid fuel crusher 100 of the present embodiment performs the classifier speed-up operation for increasing the rotation speed Rc of the rotary classifier 16 a plurality of times when the first control mode using the biomass fuel is executed. It is what you do.

FIG. 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 crushing apparatus 100 according to the present embodiment is stopped. FIG. 15 is a graph showing a change in the amount of fuel on the rotary table 12 when the operation of the solid fuel crushing apparatus 100 according to the present embodiment is stopped. In addition, in FIG. 14 and FIG. 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 with respect to the second control mode.

As shown in FIG. 14, the solid fuel crusher 100 of the present embodiment is a classifier described in the first embodiment at time T2 and time T2b in a predetermined acceleration period Ps from time T2 to time T3. Perform speed-up operation. Further, the solid fuel crusher 100 of the present embodiment executes the classifier deceleration operation described in the first embodiment at the time T2a and the time T3 in the predetermined acceleration period Ps.

The solid fuel crusher 100 of the present embodiment maintains the rotation speed Rc per unit time of the rotary classifier 16 at Rc1 during normal operation during the predetermined first transport period Pt1 from time T1 to time T2. .. At time T2, the solid fuel crusher 100 performs a classifier speed-up operation for increasing the rotation speed Rc of the rotary classifier 16 per unit time from Rc1 to Rc2, and maintains Rc2 until time T2a. At time T2a, the solid fuel crusher 100 performs a classifier deceleration operation that reduces the rotation speed Rc from Rc2 to Rc1 and maintains Rc1 until time T2b. Further, at time T2a, the rotation speed Rc of the rotary classifier 16 in the classifier deceleration operation decreases from Rc2, but may be higher than Rc1 during normal operation.

At time T2b, the solid fuel crusher 100 performs a classifier speed-up operation for increasing the rotation speed Rc of the rotary classifier 16 per unit time from Rc1 to Rc4, and maintains Rc4 until time T3. At time T3, the solid fuel crusher 100 performs a classifier deceleration operation for reducing the rotation speed Rc from Rc4 to Rc1 and maintains Rc1 until time T4. Here, Rc4 has a lower rotation speed than Rc2. This is because the bridge state of the deposited coarse-grained fuel B1 collapses at time T2, so that the centrifugal force required to discharge the deposited coarse-grained fuel B1 from the internal SP1 to the external SP2 after that is small. Further, at time T3, the rotation speed Rc of the rotary classifier 16 in the classifier deceleration operation decreases from R42, but may be higher than Rc1 during normal operation.

In the present embodiment, the rotation speed Rc is not held above the predetermined rotation speed Rcb during the entire period of the predetermined acceleration period Ps, and the rotation speed Rc is less than Rcb from the time T2a to the time T2b (the present embodiment). Then, it is set to Rc1). By repeating the speed-up operation and the deceleration operation a plurality of times, the number of times the centrifugal force applied to the deposited coarse-grained fuel B1 is changed is increased and the bridge state of the deposited coarse-grained fuel B1 is broken. This is to promote discharge from the internal SP1 to the external SP2.

As shown in FIG. 15, the amount of biomass fuel on the rotary table 12 gradually decreases from Wt3 to Wt1 by the time T2. 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 even smaller than Wt1.

In the above description, when the first control mode using the biomass fuel is executed, it is assumed that the classifier speed-up operation and the classifier deceleration operation are performed twice in the fuel discharge period Pd. However, other aspects may be used. For example, three or more times of speed-up operation of classifier and a plurality of times of deceleration of classifier may be executed.

Further, in the above description, Rc4, which is the rotation 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 it is another embodiment. You may. For example, the rotation speed Rc in the period from the time T2b to the time T3 may be made to match Rc2, or may be higher than Rc2.

According to the solid fuel crusher 100 of the present embodiment described above, since the speed-increasing operation is executed a plurality of times during the fuel discharge period Pd, it is applied to the deposited coarse-grained fuel B1 deposited in the internal SP1 of the rotary classifier 16. It is possible to increase the number of times the centrifugal force is changed, increase the breaking of the bridge state of the deposited coarse-grained fuel B1, and promote the discharge of the deposited coarse-grained fuel B1 from the internal SP1 to the external SP2.

[Other Embodiments]
In the above description, the control unit 50 reduces the rotation speed Rc of the rotary classifier 16 to less than the predetermined rotation speed Rcb according to the elapse of the predetermined acceleration period Ps, but in another embodiment, the rotation speed Rc is reduced to less than the predetermined rotation speed Rcb. There may be. For example, the control unit 50 responds to the fact that the differential pressure detected by the differential pressure detection unit 43 becomes equal to or less than a predetermined differential pressure after increasing the rotation speed Rc per unit time of the rotary classifier 16 to Rcb or more. The rotation speed Rc of the rotary classifier 16 may be reduced to less than the predetermined rotation speed Rcb.

According to such a solid fuel crusher 100, the differential pressure detection unit 43 detects the differential pressure between the internal SP1 and the external SP2 of the rotary classifier 16, and thus deposits on the internal SP1 of the rotary classifier 16. It is possible to grasp the accumulation state of the coarse-grained fuel B1. Then, the number of revolutions per unit time of the rotary classifier 16 corresponds to the decrease in the deposited coarse-grained fuel B1 deposited on the internal SP1 when the differential pressure detected by the differential pressure detection unit 43 becomes equal to or less than the predetermined differential pressure. Rc can be reduced to less than a predetermined number of revolutions Rcb.

Further, the control unit 50 sets the rotation speed Rc of the rotary classifier 16 according to the elapse of the predetermined acceleration period Ps and the differential pressure detected by the differential pressure detecting unit 43 becomes equal to or less than the predetermined differential pressure. The number of revolutions may be reduced to less than Rcb. By doing so, even if the deposited coarse-grained fuel B1 deposited on the internal SP1 is not sufficiently reduced even after the acceleration period Ps has elapsed, the rotation speed Rc of the rotary classifier 16 is predetermined. The rotation speed Rc of the rotary classifier 16 is rotated at a predetermined rotation speed Rcb or higher, and when the differential pressure becomes equal to or lower than a predetermined differential pressure, that is, when the deposited coarse-grained fuel B1 is surely reduced. It can be reduced to less than a few Rcb.

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 amount of biomass fuel on the rotary table 12 becomes a predetermined amount or more. Accordingly, the rotation speed Rc of the rotary classifier 16 may be reduced to less than the predetermined rotation speed Rcb. Further, even if it is determined that the amount of biomass fuel on the rotary table 12 is equal to or less than the predetermined amount and the classifier speed-up operation for increasing the rotation speed Rc of the rotary classifier 16 to the predetermined rotation speed Rcb or more is performed. Often, the classifier deceleration operation may be performed after the elapse of a predetermined time thereafter to end the fuel discharge period Pd.

Further, the control unit 50 stops the mill 10 in a shorter time than the predetermined time depending on the operation status of the power plant 1 or when the mill 10 cannot be stopped within a predetermined time due to the influence of the type of biomass fuel or the like. If necessary, the flow rate of the primary air supplied to the mill 10 may be increased in order to efficiently circulate the fuel inside the mill 10. For example, when the fuel discharge period Pd takes longer than a predetermined time (for example, 10 minutes to 30 minutes), the flow rate of the primary air may be increased by a certain amount (for example, about 10% to 20% of the flow rate). ..

Further, in the above description, when the rotation speed Rc of the rotary classifier 16 is increased to the predetermined rotation speed Rcb or more in the predetermined speed increase period Ps, the constant speed is maintained for a predetermined time. It may be an embodiment. For example, the rotation speed Rc of the rotary classifier 16 may be increased or decreased with a constant gradient. Further, for example, the rotation speed Rc of the rotary classifier 16 may be gradually increased or decreased.

Further, in the above description, the solid fuel used in the first control mode is assumed to be a biomass fuel, but other embodiments may be used. For example, a PC (Petroleum Coke) generated during petroleum refining may be used. Although the particle size of the PC after crushing is small and uniform, the adhesion of the crushed particles is higher than that of coal or biomass fuel, and the fuel after crushing is stored in the internal SP1 of the rotary classifier 16 as compared with coal. There is a risk of accumulation. Therefore, it is effective to control by the first control mode of the present disclosure.

The solid fuel crushing apparatus described in each of the above-described embodiments is grasped as follows, for example.
In the solid fuel crusher (100) according to the present disclosure, the solid fuel is supplied from the fuel supply unit (17) and the solid fuel is supplied to the rotary table (12) that rotates around the rotation center axis and the fuel supply unit (17). A crushing roller (13) for crushing solid fuel between a fuel supply machine (20) for supplying fuel and a rotary table (12), and a crushing roller (13) that rotates around the central axis of rotation and is provided around the central axis of rotation at predetermined intervals. A rotary classifier (16), which is provided with a plurality of classifying blades (16a) and classifies the fuel after crushing the solid fuel, and a rotary table (12), and a solid fuel by a fuel supply machine (20). The control unit (50) is provided with a control unit (50) for controlling the supply of the fuel and the rotation of the rotary classifier (16), and the control unit (50) rotates after stopping the supply of solid fuel by the fuel supply machine (20). Control to execute a speed-increasing operation that temporarily increases the number of revolutions (Rc) per unit time of the rotary classifier (16) during the fuel discharge period (Pd) until the rotation of the table (12) is stopped. To do.

According to the solid fuel crusher (100) according to the present disclosure, the fuel discharge period (Pd) from the stop of the supply of the solid fuel by the fuel supply machine (20) to the stop of the rotation of the rotary table (12). In, the number of revolutions (Rc) per unit time of the rotary classifier (16) increases. As the number of revolutions (Rc) per unit time of the rotary classifier (16) increases, the centrifugal force acting on the post-crushed fuel inside the rotary classifier (16) increases, so that the accumulated post-crushed fuel By breaking the bridge state of, the discharge of fuel after crushing from the rotary classifier (16) is promoted. Therefore, the pulverized fuel accumulated inside the rotary classifier (16) can be appropriately removed without increasing the manufacturing cost of the mill (10) and the weight of the rotary classifier (16).

In the solid fuel crusher (100) according to the present disclosure, the control unit (50) stops the supply of solid fuel by the fuel supply machine (20), and then the rotary classifier (16) is in the first transport period (Pt1). ) Is set to less than the predetermined number of revolutions (Rcb), and the number of revolutions (Rc) per unit time of the rotary classifier (16) is set after the first transport period (Pt1) has elapsed. Increase to a predetermined rotation speed (Rcb) or higher.

According to the solid fuel crusher (100) according to the present disclosure, the rotation speed (Rc) of the rotary classifier (16) is not increased in the first transport period (Pt1) after the supply of the solid fuel is stopped. The first transport period (Pt1) can be utilized to promote the discharge of the pulverized fuel retained inside the solid fuel pulverizer (100). Further, after the first transport period (Pt1) has elapsed, the crushed fuel accumulated inside the rotary classifier (16) can be appropriately removed and discharged to the outside of the rotary classifier (16). it can.

In the solid fuel crusher (100) according to the present disclosure, the control unit (50) increases the speed of the rotary classifier (16) after increasing the number of revolutions per unit time to a predetermined number of revolutions (Rb) or more. The rotation speed (Rc) per unit time of the rotary classifier (16) is reduced to less than the predetermined rotation speed (Rb) according to the elapse of the period (Ps).
According to the solid fuel crusher (100) according to the present disclosure, the rotation speed (Rc) of the rotary classifier (16) is maintained at a predetermined rotation speed (Rb) or higher until the acceleration period (Ps) elapses. Therefore, the fuel after crushing accumulated inside the rotary classifier (16) can be reliably removed. Further, since the rotation speed (Rc) per unit time of the rotary classifier (16) is reduced to less than the predetermined rotation speed (Rb) except during the speed increase period (Ps), the rotational power of the rotary classifier (16) is reduced. The cost can be reduced.

The solid fuel crusher (100) according to the present disclosure detects the differential pressure between the pressure inside the rotary classifier (16) (SP1) and the pressure outside the rotary classifier (16) (SP2). The differential pressure detection unit (43) is provided, and the control unit (50) increases the rotation speed of the rotary classifier (16) per unit time to a predetermined rotation speed (Rcb) or more, and then the differential pressure detection unit (50). The rotation speed (Rc) per unit time of the rotary classifier (16) is reduced to less than the predetermined rotation speed (Rcb) according to the differential pressure detected by 43) becoming equal to or less than the predetermined differential pressure.

According to the solid fuel crusher (100) according to the present disclosure, the differential pressure detecting unit (23) detects the differential pressure between the inside (SP1) and the outside (SP2) of the rotary classifier (16) to rotate the rotary classifier (16). It is possible to grasp the accumulation state of the crushed fuel deposited on the formula classifier (16). Then, the number of revolutions of the rotary classifier (16) is increased according to the fact that the differential pressure detected by the differential pressure detection unit (43) becomes equal to or less than the predetermined differential pressure and the amount of fuel after pulverization accumulated inside (SP1) decreases. (Rc) can be reduced to less than a predetermined number of revolutions (Rcb).

In the solid fuel crusher (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 the second. 2 Control is performed so that the rotation of the rotary classifier (16) is stopped after the transport period (Pt2) has elapsed.
According to the solid fuel crusher (100) according to the present disclosure, since the second transport period (Pt2) is provided after the acceleration period (Ps), the second transport period (Pt2) is used for rotary classification. It is possible to promote the discharge of the crushed fuel discharged from the inside of the machine (16) to the outside of the device.

In the solid fuel crusher (100) according to the present disclosure, the control unit (50) controls to execute the speed-increasing operation a plurality of times during the fuel discharge period (Pd).
According to the solid fuel crusher (100) according to the present disclosure, since the speed-increasing operation is executed a plurality of times during the fuel discharge period (Pd), the crushed fuel deposited inside the rotary classifier (16) is affected. It is possible to increase the number of times the centrifugal force is changed, make it easier to break the bridge state of the accumulated crushed fuel, and promote the discharge of the crushed fuel from the inside (SP1) to the outside (SP2).

In the solid fuel crusher (100) according to the present disclosure, the control unit (50) has a first control mode for executing a speed-increasing operation during the fuel discharge period (Pd), and a unit time of the rotary classifier (16). It is possible to selectively execute the second control mode in which the rotation speed (Rc) per rotation is maintained at a constant rotation speed (Rc3).
According to the solid fuel crusher (100) according to the present disclosure, the first control mode for executing the speed-increasing operation and the second control for maintaining the rotation speed (Rc) at a constant rotation speed according to the type of the solid fuel. Modes and modes can be selectively executed.

The power plant (1) including the solid fuel crusher (100) described in each of the above-described embodiments is grasped as follows, for example.
The power generation plant (1) according to the present disclosure is a boiler that produces steam by burning the solid fuel crusher (100) according to any one of the above and the solid fuel crushed by the solid fuel crusher (100). (200) and a power generation unit that generates electricity using the steam generated by the boiler (200).
According to the power plant (1) according to the present disclosure, the crushed fuel deposited inside the rotary classifier is appropriate without increasing the manufacturing cost of the mill (10) or the weight of the rotary classifier (16). Can be removed.

The control method of the solid fuel crusher (100) described in each of the above-described embodiments can be grasped as follows, for example.
The control method of the solid fuel crusher (100) according to the present disclosure includes a rotary table (12) in which solid fuel is supplied from the fuel supply unit (17) and rotates around the central axis of rotation, and a fuel supply unit (17). A fuel supply machine (20) that supplies solid fuel to the vehicle, a crushing roller (13) that crushes the solid fuel between the rotary table (12), and a predetermined rotation center axis while rotating around the rotation center axis. In a solid fuel crusher (100) provided with a rotary classifier (16) having a plurality of classifying blades (16a) provided at intervals and classifying the crushed fuel after crushing by a crushing roller (13). , The fuel discharge period (Pd) has elapsed since the first stop step (S104) for stopping the supply of solid fuel by the fuel supply machine (20) and the solid fuel supply for stopping the supply in the first stop step (S104). In the second stop step (S110) for stopping the rotation of the rotary table (12) later and the fuel discharge period (Pd), the speed increase for increasing the rotation speed (Rc) per unit time of the rotary classifier (16). A step (S106) is provided.

According to the control method of the solid fuel crusher (100) according to the present disclosure, the fuel discharge period from when the supply of solid fuel by the fuel supply machine (20) is stopped to when the rotation of the rotary table (12) is stopped ( In Pd), the rotation speed (Rc) of the rotary classifier (16) increases. As the rotation speed (Rc) of the rotary classifier (16) increases, the centrifugal force acting on the post-crushed fuel inside the rotary classifier (16) increases, so that the accumulated post-crushed fuel is in a bridge state. After crushing, the discharge of fuel from the rotary classifier (16) is promoted. Therefore, the pulverized fuel accumulated inside the rotary classifier (16) can be appropriately removed without increasing the manufacturing cost of the mill (10) and the weight of the rotary classifier (16).

1 Power plant 10 Mill 11 Housing 12 Rotating table 13 Roller (crushing roller)
14 Drive unit 16 classifier (rotary classifier)
16a blade (classification blade)
16b Fixed part 17 Fuel supply part 18 Motor 19 Outlet 20 Coal dispenser (fuel supply machine)
22 Transport section (fuel supply machine)
23 Motor (fuel supply machine)
30 Blower (gas supply for transportation)
30a Hot gas blower 30b Cold gas blower 30c Hot gas damper (1st blower)
30d cold gas damper (second blower)
40 State detection unit (temperature detection means, differential pressure detection means)
41 Bottom part 42 Ceiling part 43 Differential pressure detection part 50 Control part 100 Solid fuel crusher 100a Primary air flow path (gas flow path for transportation)
100b Supply flow path 200 Boiler 210 Fireplace 220 Burner (combustion device)
B1 Coarse grain fuel F1 Flow inside rotary classifier SP1 (for rotary classifier) Internal SP2 (for rotary classifier) External SP3 (below rotary classifier) Space Rc (for rotary classifier) Rotation number Rt (rotation table) rotation number

Claims (9)

A rotary table that rotates around the center axis of rotation while solid fuel is supplied from the fuel supply unit,
A fuel supply machine that supplies the solid fuel to the fuel supply unit,
A crushing roller for crushing the solid fuel between the rotary table and the rotary table.
A rotary classifier that rotates around the central axis of rotation and is provided with a plurality of classifying blades provided around the central axis of rotation at predetermined intervals to classify the crushed fuel after crushing the solid fuel.
A control unit for controlling the rotation of the rotary table, the supply of the solid fuel by the fuel supply machine, and the rotation of the rotary classifier is provided.
The control unit temporarily determines the number of revolutions per unit time of the rotary classifier during the fuel discharge period from the stop of the supply of the solid fuel by the fuel supply machine to the stop of the rotation of the turntable. A solid fuel crusher that controls to perform speed-up operations that increase to. The control unit sets the number of revolutions per unit time of the rotary classifier to less than a predetermined number of revolutions during the first transport period after stopping the supply of the solid fuel by the fuel supply machine, and the first transport period is After a lapse of time, the number of revolutions per unit time of the rotary classifier is increased to the predetermined number of revolutions or more, and the predetermined number of revolutions is the action of centrifugal force due to the rotation of the crushed fuel inside the rotary classifier. The solid fuel crushing apparatus according to claim 1, which is the number of revolutions at which the rotary classifier starts to discharge. 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 rotates the rotary classifier per unit time according to the elapse of the acceleration period. The solid fuel crushing apparatus according to claim 2, wherein the number is reduced to less than the predetermined number of revolutions. A differential pressure detecting unit for detecting a differential pressure between the pressure inside the rotary classifier and the pressure outside the rotary classifier is provided.
The control unit responds to the fact that the differential pressure detected by the differential pressure detection unit becomes equal to or less than the predetermined differential pressure after increasing the rotation speed per unit time of the rotary classifier to the predetermined rotation speed or more. The solid fuel crushing apparatus according to claim 2, wherein the number of revolutions per unit time of the rotary classifier is reduced to less than the predetermined number of revolutions. The control unit controls to stop the rotation of the rotary classifier after the second transport period elapses after reducing the number of revolutions per unit time of the rotary classifier to less than the predetermined number of revolutions. The solid fuel crusher according to claim 3 or 4. The solid fuel crushing device according to any one of claims 1 to 5, wherein the control unit controls the acceleration operation to be executed a plurality of times during the fuel discharge period. The control unit sets the rotation speed per unit time of the rotary classifier to a constant rotation speed in the first control mode for executing the speed-up operation during the fuel discharge period according to the type of the solid fuel. The solid fuel crushing apparatus according to any one of claims 1 to 6, wherein the second control mode to be maintained can be selectively executed. The solid fuel crusher according to any one of claims 1 to 7.
A boiler that burns solid fuel crushed by the solid fuel crusher to generate steam, and
A power generation unit that generates electricity using the steam generated by the boiler,
Power plant equipped with. A rotary table that rotates around the center axis of rotation while solid fuel is supplied from the fuel supply unit,
A fuel supply machine that supplies the solid fuel to the fuel supply unit,
A crushing roller for crushing the solid fuel between the rotary table and the rotary table.
A rotary classifier that rotates around the rotation center axis and is provided around the rotation center axis at predetermined intervals, and classifies the crushed fuel after crushing the solid fuel. It is a control method of the solid fuel crusher.
The first stop step of stopping the supply of the solid fuel by the fuel supply machine, and
A second stop step of stopping the rotation of the rotary table after the fuel discharge period has elapsed since the supply of the solid fuel was stopped in the first stop step.
A control method for a solid fuel crusher comprising a speed-increasing step of temporarily increasing the number of revolutions per unit time of the rotary classifier during the fuel discharge period.

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