JP2019066121A - Solid fuel pulverization device and control method of solid fuel pulverization device - Google Patents

Abstract

To improve responsiveness to increase or decrease of a load of a boiler and followability to a target value load of the load of the boiler in a case of increasing or decreasing the load of the boiler.SOLUTION: A solid fuel pulverization device includes a first calculation portion for calculating a reference rotating speed command value Rst of a pulverization table according to a load of a boiler, a second calculation portion for calculating an additional rotating speed command value of the pulverization table according to the load, and a control portion for controlling the rotating speed of the pulverization table driven by a driving portion on the basis of the target rotating speed command value Rta obtained by adding the additional rotating speed command value to the reference rotating speed command value Rst. In a case when a load command to increase the load of the boiler from a first load L1 to a second load L2 is input, the second calculation portion gradually decreases the additional rotating speed command value from an initial value Rad0 to zero according to the increase of the load.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a solid fuel grinding device and a control method of the solid fuel grinding device.

For example, in a coal-fired thermal power plant, steam is generated by heat exchange with combustion gas generated by burning pulverized coal pulverized by a coal pulverizer in a boiler furnace, and power generation is performed by driving a turbine using the steam. It is carried out.
Here, the load (power generation output) during operation of the coal-fired thermal power plant is not necessarily constant, and an operation involving a load change may be performed. For example, when a coal-fired thermal power plant is linked to an electric power system, the load of the coal-fired thermal power plant may be rapidly changed according to the request of the system side for the purpose of stabilization of the system frequency.

However, in a coal-fired thermal power plant, even if the amount of supply of coal to the coal pulverizer is changed, a time lag (coal retard) occurs before the amount of coal output from the coal pulverizer changes. For this reason, it is difficult to quickly change the load of a coal-fired power plant.
In this respect, Patent Document 1 determines the rotational speed of the table (crushing table) based on the coal feeding amount command value and the parameter relating to the change in the load of the generator in order to eliminate the delayed coal output. Is disclosed. Further, in Patent Document 2, the amount of coal supply is increased or decreased corresponding to the increase or decrease of the load of the vertical mill, and the excess or deficiency of the amount of coal output based on the time delay from the coal supply to the coal extraction is compensated. There is disclosed a control method of a vertical mill adapted to increase or decrease the rotational speed.

Unexamined-Japanese-Patent No. 2015-100740 JP-A-63-62556

Patent Document 1 determines the base rotation speed of a table based on the amount of coal supply, determines the advance rotation speed based on the change rate of load required for the generator, etc., and adds the advance rotation speed to the base rotation speed. To determine the rotation speed of the table.
However, in Patent Document 1, as shown in FIG. 6, the leading rotation speed is sequentially calculated and added to the base rotation speed until the generator load reaches the target load. Therefore, the time change of the rotation speed of the table becomes excessively large, the driving power of the drive unit for temporarily rotating the table increases, and the amount of crushed coal may not be stabilized. When the type of coal is different, it is necessary to set the coefficient of the function that controls the table rotation speed again by testing or the like, and when there are a plurality of functions and coefficients, it is easy to be complicated.

In addition, as shown in FIG. 5, Patent Document 2 gradually increases from zero the set value for increasing the rotational speed of the table simultaneously with the load command for increasing the boiler load, and the boiler load reaches the target load. After that, the setting value is gradually decreased and returned to zero.
However, in Patent Document 2, since the set value is gradually increased with respect to the load command, the responsiveness of the increase in the rotational speed of the table to the load command may be insufficient. In addition, since the set value is gradually decreased after the boiler load reaches the target load, the boiler load may increase excessively beyond the target load.

  The present disclosure has been made in view of such circumstances, and when the load on the boiler is increased or decreased, the responsiveness of the rotation speed of the grinding table to the increase or decrease in the load on the boiler, and the load on the boiler It is an object of the present invention to provide a solid fuel grinding device and its control method capable of enhancing the followability to the target value load of the above.

In order to solve the above-mentioned subject, this indication adopts the following means.
A solid fuel pulverizing apparatus according to an aspect of the present disclosure is a solid fuel pulverizing apparatus that pulverizes solid fuel and supplies the pulverized solid fuel to a boiler, the pulverizing table, and a drive unit generating a driving force for rotating the pulverizing table. A roller for grinding the solid fuel supplied from the fuel supply unit to the grinding table with the grinding table, and the solid fuel ground by the roller is classified into a pulverized fuel smaller than a predetermined particle diameter to obtain the solid A classification unit for unloading from the fuel crushing apparatus, a first calculation unit for calculating a reference rotation speed command value of the crushing table according to the load of the boiler, and an additional rotation speed command value of the crushing table according to the load The crushing table driven by the drive unit based on a second calculation unit to calculate and a target rotation speed command value obtained by adding the additional rotation speed command value to the reference rotation speed command value And a control unit configured to control the number of revolutions, and when a load command to increase the load of the boiler from the first load to the second load is input, the second calculation unit is configured to respond to the increase in the load. The addition rotational speed command value is gradually decreased from the initial value to zero.

  According to the solid fuel pulverizing apparatus according to one aspect of the present disclosure, when a load command for increasing the load of the boiler is input, an initial value greater than zero is given as the additional rotation speed command value, and therefore, the pulverization to the load command is performed. The responsiveness of the increase in the rotational speed of the table (also called a rotary table) can be enhanced. Moreover, since the addition rotation speed command value gradually decreases from the initial value to zero according to the increase in load, the rotation speed of the crushing table is set to the reference rotation speed command value when the load on the boiler becomes the second load. The speed can be adapted to Therefore, the load of the boiler does not rise excessively beyond the target load, and the followability to the target load can be enhanced using a simple addition rotational speed command value.

In the solid fuel pulverizing apparatus according to one aspect of the present disclosure, the second calculation is performed when a load command for increasing the load of the boiler from the first load to a third load that is larger than the second load is input. The unit gradually decreases the addition rotational speed command value from the initial value to zero according to the increase from the first load to the second load, and increases the second load to the third load. Accordingly, the addition rotational speed command value may be gradually decreased from the initial value to zero.
When increasing the load of the boiler from the first load to the third load that is larger than the second load, the additional rotation speed command value becomes zero at the second load, so the addition rotation from the first load to the third load Compared with the case where the number command value is maintained at a value larger than zero, an excessive increase in the number of rotations of the grinding table is prevented. Therefore, it is suppressed that the amount of coal output excessively increases with the increase in the rotation speed of a grinding table.

In the solid fuel pulverizing apparatus according to an aspect of the present disclosure, the second calculation unit may set the initial value in accordance with the increase amount of the load per unit time.
By setting an initial value according to the amount of increase in load per unit time, an appropriate initial value according to the amount of increase in load per unit time can be set, and the followability of the rotation speed of the grinding table to the change in load It is possible to suppress an excessive increase in the amount of coal output while increasing the

In the solid fuel pulverizing apparatus according to one aspect of the present disclosure, the second calculation unit may set the additional rotation speed command value to zero when the load is lower than a predetermined load.
In this way, when the load is lower than the predetermined load that is unlikely to cause coal output delay, the rotation speed of the crushing table can be made a value according to the reference rotation speed command value.

  In the solid fuel crushing apparatus according to an aspect of the present disclosure, the second calculation unit calculates a subtraction rotation speed command value of the crushing table according to the load, and the load of the boiler is calculated based on the second load. When a load command to reduce to one load is input, the second calculation unit may gradually decrease the subtraction rotational speed command value from an initial value to zero according to the decrease of the load.

  According to the solid fuel pulverizing apparatus according to one aspect of the present disclosure, when a load command for reducing the load on the boiler is input, an initial value larger than zero is given as the subtraction rotational speed command value, and therefore the pulverization for the load command is performed. It is possible to increase the responsiveness of the reduction of the table rotation speed. Also, since the subtraction rotation speed command value gradually decreases from the initial value to zero according to the decrease in load, the rotation speed of the crushing table is set to the reference rotation speed command value when the load on the boiler becomes the first load. The speed can be adapted to Therefore, the load of the boiler does not decrease excessively beyond the target load, and the followability to the target load can be enhanced using a simple subtraction rotational speed command value.

In the solid fuel pulverizing apparatus according to one aspect of the present disclosure, the second calculation is performed when a load command for reducing the load of the boiler from a third load larger than the second load to the first load is input. The unit gradually decreases the subtraction rotational speed command value from the initial value to zero in response to the reduction from the third load to the second load, and reduces the second load to the first load. In response, the subtraction rotational speed command value may be gradually decreased from the initial value to zero.
When reducing the load of the boiler from the third load to the first load, which is larger than the second load, the subtraction rotational speed command value becomes zero at the second load, so the rotation is subtracted from the third load to the first load As compared with the case where the number command value is maintained at a value larger than zero, an excessive decrease in the number of revolutions of the grinding table is prevented. Therefore, it is suppressed that the amount of coal output decreases excessively with the reduction of the number of rotations of a grinding table.

In the solid fuel pulverizing apparatus according to an aspect of the present disclosure, the second calculation unit may set the initial value in accordance with the decrease amount of the load per unit time.
By setting an initial value according to the amount of decrease in load per unit time, an appropriate initial value according to the amount of decrease in load per unit time can be set, and the followability of the rotation speed of the grinding table to changes in load It is possible to suppress an excessive decrease in the amount of coal output while increasing the

  A control method of a solid fuel pulverizing apparatus according to an aspect of the present disclosure is a control method of a solid fuel pulverizing apparatus that pulverizes solid fuel and supplies the pulverized solid fuel to a boiler, wherein the solid fuel pulverizing apparatus comprises: a pulverizing table; A driving unit for generating a driving force for rotating the table, a roller for grinding the solid fuel supplied from the fuel supply unit to the grinding table with the grinding table, and the solid fuel ground by the roller A first calculating step of calculating a reference rotation number command value of the crushing table according to the load of the boiler, and classifying the fine fuel smaller than the predetermined particle diameter and discharging the solid fuel crushing device out of the solid fuel crushing device And a second calculation step of calculating an additional rotation speed command value of the crushing table according to the load, and a target rotation speed finger obtained by adding the additional rotation speed command value to the reference rotation speed command value. Control step of controlling the number of rotations of the grinding table driven by the drive unit based on a value, and a load command to increase the load of the boiler from the first load to the second load is input. The second calculation step gradually decreases the addition rotational speed command value from an initial value to zero according to the increase of the load.

  According to the control method of the solid fuel pulverizing apparatus according to one aspect of the present disclosure, when a load command for increasing the load of the boiler is input, an initial value larger than zero is given as the additional rotation speed command value. The responsiveness of the increase in rotational speed of the grinding table to the command can be enhanced. Moreover, since the addition rotation speed command value gradually decreases from the initial value to zero according to the increase in load, the rotation speed of the crushing table is set to the reference rotation speed command value when the load on the boiler becomes the second load. The speed can be adapted to Therefore, the load of the boiler does not rise excessively beyond the target load, and the followability to the target load can be enhanced using a simple addition rotational speed command value.

  A control method of a solid fuel pulverizing apparatus according to an aspect of the present disclosure includes a third calculating step of calculating a subtraction rotational speed command value of the pulverizing table according to the load, and a load of the boiler is set to a second load from a second load. When the load command to reduce to one load is input, the third calculation step may gradually decrease the subtraction rotational speed command value from the initial value to zero according to the decrease of the load.

  According to the control method of the solid fuel pulverizing apparatus according to one aspect of the present disclosure, when a load command for reducing the load on the boiler is input, an initial value larger than zero is given as the subtraction rotation speed command value. It is possible to increase the responsiveness of the reduction of the rotation speed of the grinding table to the command. Also, since the subtraction rotation speed command value gradually decreases from the initial value to zero according to the decrease in load, the rotation speed of the crushing table is set to the reference rotation speed command value when the load on the boiler becomes the first load. The speed can be adapted to Therefore, the load of the boiler does not decrease excessively beyond the target load, and the followability to the target load can be enhanced using a simple subtraction rotational speed command value.

  According to the present disclosure, when increasing or decreasing the load of the boiler, the responsiveness of the rotation speed of the grinding table to the increase or decrease of the load of the boiler and the followability of the load of the boiler to the target value load can be improved. A solid fuel grinding device and a control method thereof can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the solid fuel crushing apparatus and boiler of 1st Embodiment of this indication. It is a block diagram which shows schematic structure of the control apparatus shown in FIG. It is a figure which shows the relationship of the boiler load and rotation speed command value in the case of making a boiler load increase from a 1st load to a 2nd load in the solid fuel crushing apparatus concerning 1st Embodiment. It is a figure which shows the relationship of the boiler load and rotation speed command value in the case of reducing a boiler load from a 2nd load to a 1st load in the solid fuel crushing apparatus concerning 1st Embodiment. It is a figure which shows the time change of the amount of coal removal from a solid fuel crushing apparatus to a boiler in the case of making a boiler load increase in the solid fuel crushing apparatus concerning 1st Embodiment. It is a figure which shows the relationship of the boiler load and rotation speed command value in the case of making a boiler load increase from a 1st load to a 2nd load in the solid fuel crushing apparatus concerning 2nd Embodiment. It is a figure which shows the relationship of the boiler load and rotation speed command value in the case of making a boiler load increase from a 1st load to a 3rd load in the solid fuel crushing apparatus concerning 3rd Embodiment. It is a figure which shows the relationship of the boiler load and rotation speed command value in the case of reducing a boiler load from a 3rd load to a 1st load in the solid fuel crushing apparatus concerning 3rd Embodiment. It is a figure which shows the relationship between a boiler load change rate, the initial value of addition rotation speed command value, and the initial value of subtraction rotation speed command value in the solid fuel crushing apparatus concerning 4th Embodiment.

Hereinafter, an embodiment of a solid fuel grinding device and a control method thereof according to the present disclosure will be described with reference to the drawings.
First Embodiment
Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings.
The solid fuel pulverizing apparatus 100 of the present embodiment is an apparatus for pulverizing carbon-containing solid fuel such as coal, generating pulverized fuel, and supplying the pulverized fuel to a burner unit (combustion apparatus) 220 of the boiler 200.
The boiler system including the solid fuel pulverizing apparatus 100 and the boiler 200 shown in FIG. 1 is provided with one solid fuel pulverizing apparatus 100, but corresponds to each of the plurality of burner units 220 of one boiler 200. A system including a plurality of solid fuel pulverizing apparatuses 100 may be used.

The solid fuel pulverizing apparatus 100 of the present embodiment includes a mill 10, a coal feeder 20, a blower 30, a temperature detector 40, and a controller 50.
In the present embodiment, the upper side indicates the direction of the vertically upper side, and the “upper” such as the upper side or the upper side indicates the vertically upper portion. Similarly, "lower" indicates a vertically lower portion.

The mill 10 has a housing 11, a grinding table 12, a roller 13, a drive unit 14, a drive shaft 15, a classification unit 16, a fuel supply unit 17, and a motor 18 for rotationally driving the classification unit 16. .
The housing 11 is formed in a substantially cylindrical shape extending in the vertical direction, and is a housing that accommodates the crushing table 12, the roller 13, the classification unit 16, and the fuel supply unit 17.

  The crushing table 12 is a circular member in plan view that is rotated by a driving force transmitted from the driving unit 14 through the driving shaft 15, and is supplied with solid fuel (for example, coal in the present embodiment) from the fuel supply unit 17. The solid fuel powder is crushed between the roller 13 and is also called a rotary table. At a plurality of locations on the outer peripheral side of the grinding table 12, there are provided outlets (not shown) that allow the primary air flowing from the primary air flow path 100a as the carrier gas to flow out into the space above the grinding table 12 in the housing 11. ing.

  A vane (not shown) is installed above the air outlet to apply a swirling force to the primary air blown from the air outlet. The primary air to which a swirling force is given by the vanes turns into an air flow having a swirling velocity component and blows up the solid fuel pulverized on the pulverizing table 12 and leads it to the classification portion 16 in the upper part of the housing 11. Among the pulverized solid fuel mixed with the primary air, one having a particle diameter larger than the predetermined particle diameter is classified by the classifying unit 16 or dropped without reaching the classifying unit 16 and returned to the upper surface of the crushing table 12.

  The roller 13 is a rotating body that crushes the solid fuel supplied from the fuel supply unit 17 to the upper surface of the crushing table 12 with the crushing table 12. The roller 13 is pressed against the upper surface of the grinding table 12 and cooperates with the grinding table 12 to grind the solid fuel. Although only one roller 13 is shown in FIG. 1, the plurality of rollers 13 are disposed at regular intervals in the circumferential direction so as to press the upper surface of the grinding table 12. For example, three rollers 13 are disposed at an angular interval of 120 ° on the outer peripheral portion. In this case, in a portion (a pressing portion) in which the three rollers 13 are in contact with the upper surface of the grinding table 12, the distances from the center of the grinding table 12 are substantially equal.

The driving unit 14 is a device that transmits the driving force to the crushing table 12 via the driving shaft 15 and rotates the crushing table 12 about a central axis. The driving unit 14 generates a driving force for rotating the grinding table 12.
The classifying unit 16 is a solid fuel pulverized by the roller 13 that is larger than a predetermined particle size (for example, 70 to 100 μm) (hereinafter, the pulverized solid fuel having a predetermined particle size is referred to as “coarse powder fuel”). It is an apparatus which classifies into the thing below a predetermined particle size (Hereafter, the crushed solid fuel below a predetermined particle size is called "fine-powder fuel."). The classifying portion 16 has, for example, a truncated conical outer shape, is attached to the upper side in the housing 11 along the cylindrical axis of the substantially cylindrical housing 11, and includes a plurality of classifying blades on the outer peripheral side. The classification unit 16 is driven by the motor 18 and rotates about the cylindrical axis of the housing 11.

  The pulverized solid fuel mixed in the primary air that has reached the classification section 16 has the coarse fuel pulverized on the grinding table 12 due to the relative balance between the centrifugal force generated by the rotation of the classification blade and the centripetal force of the primary air flow. Then, the pulverized fuel (in the present embodiment, for example, pulverized coal fuel) is introduced from the housing 11 to the outlet 19 and carried out. The pulverized fuel classified by the classification unit 16 is mixed with primary air and discharged from the outlet 19 to the supply flow passage 100b. The pulverized fuel mixed with the primary air that has flowed out to the supply flow path 100 b is supplied to the burner unit 220 of the boiler 200.

  The fuel supply unit 17 is attached so as to penetrate the upper end of the housing 11 and supplies the solid fuel introduced from the upper portion to a substantially central region of the grinding table 12. The fuel supply unit 17 is supplied with solid fuel from the coal feeder 20.

  The coal feeder 20 has a hopper 21, a transport unit 22, and a motor 23. The transport unit 22 transports the solid fuel discharged from the lower end of the hopper 21 by the driving force applied from the motor 23, and guides the solid fuel to the fuel supply unit 17 of the mill 10 while the supply amount of the solid fuel is controlled by the controller 50. .

The blower unit 30 is a device for drying the solid fuel pulverized by the roller 13 and blowing the primary air as a carrier gas for supplying to the classification unit 16 to the inside of the housing 11.
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 for blowing heated primary air supplied via a heat exchanger (heater) such as an air preheater using the combustion gas of the boiler 200 as a heat source. A heat gas damper (first air blower) 30c is provided downstream of the heat gas blower 30a. The opening degree of the thermal gas damper 30 c is controlled by the controller 50. The flow rate of the primary air blown by the heat gas blower 30a is determined by the opening degree of the heat gas damper 30c.

  The cold gas blower 30b is a blower that blows primary air that is ambient air at normal temperature. A cold gas damper (second blower) 30d is provided downstream of the cold gas blower 30b. The opening degree of the cold gas damper 30 d is controlled by the controller 50. The flow rate of primary air that the cold gas blower 30b blows is determined by the opening degree of the cold gas damper 30d. The flow rate of the primary air is the sum of the flow rate of the primary air blown by the hot gas blower 30a and the flow rate of the primary air blown by the cold gas blower 30b, and the temperature of the primary air is the primary air blown by the hot gas blower 30a It is determined by the mixing ratio of the primary air which the cold gas blower 30b blows, and is controlled by the control device 50.

  The temperature detection unit 40 is a sensor that detects the temperature of the outlet 19. The temperature detection unit 40 detects the temperature of the pulverized fuel discharged from the outlet 19 and outputs the temperature to the control device 50.

  The control device 50 is a device that controls each part of the solid fuel pulverizing device 100. The control device 50 controls the number of rotations of the grinding table 12 by transmitting a drive instruction to the drive unit 14. Further, the control device 50 can adjust the solid fuel supply amount supplied to the fuel supply unit 17 by transferring the solid fuel by transmitting the solid fuel by transmitting the drive instruction to the motor 23 of the feeder 20. . Further, the control device 50 can control the flow rate and temperature of the primary air by controlling the opening degree of the heat gas damper 30c and the cold gas damper 30d by transmitting the opening degree instruction to the blowing unit 30.

Next, the boiler 200 which performs combustion using the pulverized fuel supplied from the solid fuel pulverizing apparatus 100 to generate steam will be described.
The boiler 200 includes a furnace 210 and a burner unit 220.

  The burner unit 220 is a device that burns the pulverized fuel using the primary air containing the pulverized fuel supplied from the supply flow passage 100 b and the secondary air supplied from the heat exchanger (not shown). 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 or an economizer.

The combustion gas discharged from the boiler 200 is subjected to predetermined processing by an environmental device such as a NOx removal device, and is also sent to a heat exchanger (heater; not shown) such as an air preheater to exchange heat with the outside air. . Outside air heated by heat exchange with the combustion gas in the heat exchanger is sent to the above-described hot gas blower 30a.
The feed water to each heat exchanger of the boiler 200 is heated in an economizer (not shown) and then further heated by an evaporator (not shown) and a superheater (not shown) to generate high temperature / high pressure steam It is sent to a turbine (not shown), and a generator (not shown) is rotationally driven to generate power.

Next, control of the rotation speed of the grinding table 12 by the control device 50 will be described.
The controller 50 increases the solid fuel supply amount supplied from the feeder 20 to the fuel supply unit 17 when increasing the load on the boiler 200. At this time, the control device 50 reduces the supply delay of the solid fuel supplied from the solid fuel pulverizing device 100 to the boiler 200, that is, the delay in timing at which the amount discharged from the solid fuel pulverizing device increases (laging delay). As such, the rotation speed of the grinding table 12 is increased. The control device 50 transmits the target rotation speed command value Rta to the drive unit 14 to rotate the crushing table 12 at the rotation speed corresponding to the target rotation speed command value Rta. Hereinafter, the process in which the control device 50 calculates the target rotation speed command value Rta will be described.

  The control device 50 is a device that controls the number of rotations of the grinding table 12 based on the target load of the boiler 200. At this time, the time to reach the end load with respect to the start time of the load change of the boiler 200 can be set by the increase amount of load per unit time (load change rate of the boiler). Furthermore, the present load of the boiler 200 may be detected to improve the controllability. In the present embodiment, a case where the detection unit 52 detects the load of the boiler 200 will be described.

  FIG. 2 is a block diagram showing a schematic configuration of the control device 50. As shown in FIG. The control device 50 includes a control unit 51, a detection unit 52, a first calculation unit 53, and a second calculation unit 54. Here, the control unit 51, the detection unit 52, the first calculation unit 53, and the second calculation unit 54 may be configured by hardware including an arithmetic device such as a CPU. The control unit 51, the detection unit 52, the first calculation unit 53, and the second calculation unit 54 may be configured as software executed by a single or a plurality of arithmetic devices.

  The control unit 51 controls the rotation speed of the crushing table 12 based on the target rotation speed command value Rta by calculating the target rotation speed command value Rta and transmitting it to the drive unit 14. The control unit 51 calculates the target rotation speed command value Rta of the crushing table 12 by adding the addition rotation speed command value Rad to a reference rotation speed command value Rst described later.

  The detection unit 52 may detect the load of the boiler 200 by the flow rate of steam generated by the boiler 200, for example, and based on the amount of power generation of a generator connected to a steam turbine driven by the steam generated by the boiler 200 The load of the boiler 200 may be detected.

  The first calculation unit 53 calculates a reference rotation speed command value Rst of the crushing table 12 according to the load of the boiler 200 detected by the detection unit 52. FIG. 3 is a diagram showing the relationship between the boiler load and the rotation speed command value R when the load (boiler load) of the boiler 200 is increased from the first load L1 to the second load L2. The reference rotation speed command value Rst calculated by the first calculation unit 53 is a value that increases in proportion to the load of the boiler 200, as indicated by a broken line in FIG.

  The reason that the reference rotational speed command value Rst is proportional to the load of the boiler is that the supply amount of solid fuel supplied from the coal feeder 20 to the solid fuel pulverizing apparatus 100 increases in proportion to the increase of the load of the boiler 200 And adjusting the pressing force of the grinding table 12 and the roller 13 in order to change the grinding capacity of the solid fuel accordingly and optimize the thickness of the solid fuel layer between the grinding table 12 and the roller 13 By increasing the rotational speed of the grinding table 12, it is possible to suppress an increase in differential pressure of the mill and an occurrence of abnormal vibration caused by insufficient grinding of the mill 10, and the solid fuel supplied from the solid fuel grinding device 100 to the boiler 200. This is because the delay (the coal output delay) at which the supply amount increases increases. The first calculation unit 53 stores in advance, for example, a test or the like on solid fuel using a table indicating the relationship between the boiler load and the reference rotational speed command value Rst indicated by a broken line in FIG. Then, the first calculation unit 53 refers to the load of the boiler 200 detected by the detection unit 52, calculates the reference rotation speed command value Rst, and transmits the reference rotation speed command value Rst to the control unit 51.

  The second calculation unit 54 calculates an additional rotation speed command value Rad according to the load of the boiler 200 detected by the detection unit 52. When a load command to increase the load of the boiler 200 from the first load L1 to the second load L2 is input from the operator (not shown) to the control device 50, the second calculation unit 54 responds to the increase of the load The addition rotational speed command value Rad is calculated so as to gradually decrease from the initial value Rad0 to zero.

  The target rotation speed command value Rta shown in FIG. 3 is obtained by adding the additional rotation speed command value Rad calculated by the second calculation unit 54 to the reference rotation speed command value Rst calculated by the first calculation unit 53. The target rotation speed command value Rta shown by a solid line in FIG. 3 is a rotation with respect to the boiler load when a load command for increasing the load to the second load L2 is input while the detection unit 52 detects the first load L1. It shows the change of the number command value R.

  As shown in FIG. 3, when a load command is input in a state where the detection unit 52 detects the first load L1, the second calculation unit 54 calculates an initial value Rad0 as the addition rotation speed command value Rad. , To the control unit 51. The control unit 51 adds the initial value Rad0 to the reference rotation speed command value Rst1 at the first load L1 calculated by the first calculation unit 53 to calculate the rotation speed command value Rta1. The rotation speed command value Rta1 becomes the target rotation speed command value Rta for the first load L1.

As shown in FIG. 3, the target rotation speed command value Rta increases in proportion to the boiler load until the boiler load reaches from the first load L1 to the second load L2, and at the second load L2, the target rotation speed command value Rta Coincides with the reference rotational speed command value Rst. This is because the addition rotational speed command value Rad calculated by the second calculation unit 54 at the second load L2 is zero. Thus, the second calculation unit 54 calculates the additional rotation speed command value Rad so as to gradually decrease from the initial value Rad0 to zero according to the increase in the load of the boiler 200.
The target rotation speed command value Rta is transmitted from the control device 50 to the drive unit 14 to control the rotation speed of the grinding table 12. The number of revolutions of the grinding table 12 may be controlled by, for example, an inverter, for example, the number of revolutions of a drive motor (not shown) of the drive unit 14.

As described above, when a load command to increase the load of the boiler 200 from the first load L1 to the second load L2 is input, the second calculation unit 54 changes the initial value Rad0 from zero to zero according to the increase in load. The addition rotational speed command value Rad is calculated so as to gradually decrease until it reaches the end.
There is less delay in the timing at which the amount of solid fuel supplied from the solid fuel pulverizing apparatus 100 to the boiler 200 increases (coalling delay), and the load on the boiler does not rise excessively beyond the target load, which is simple. It is possible to improve the followability to the target load by using the additional rotation speed command value.

  On the other hand, when a load command to reduce the load of the boiler 200 from the second load L2 to the first load L1 is input, the second calculator 54 gradually decreases from the initial value Rsu0 to zero according to the decrease in load. The subtraction rotational speed command value Rsu is calculated so that

  As shown in FIG. 4, when a load command to reduce the boiler load to the first load L1 is input in a state where the detection unit 52 detects the second load L2, the second calculation unit 54 calculates the subtraction rotational speed An initial value Rsu0 is calculated as the command value Rsu, and transmitted to the control unit 51. The control unit 51 subtracts the initial value Rsu0 from the reference rotation speed command value Rst1 at the first load L1 calculated by the first calculation unit 53 to calculate the rotation speed command value Rta2. The rotation speed command value Rta2 becomes the target rotation speed command value Rta for the second load L2.

As shown in FIG. 4, the target rotation speed command value Rta decreases in proportion to the boiler load until the boiler load reaches from the second load L2 to the first load L1, and at the first load L1, the target rotation speed command value Rta Coincides with the reference rotational speed command value Rst. This is because the subtraction rotation speed command value Rsu calculated by the second calculation unit 54 at the first load L1 is zero. As described above, the second calculation unit 54 calculates the subtraction rotation speed command value Rsu so as to gradually decrease from the initial value Rsu0 to zero from the initial value Rsu0 according to the decrease in the load of the boiler 200.
The delay (decarburization delay) at which the amount of solid fuel supplied from the solid fuel pulverizer 100 to the boiler 200 decreases decreases, and the load on the boiler does not excessively decrease beyond the target load, which is simple. It is possible to improve the followability to the target load by using the reduced production rotational speed command value.

  That is, the amount of solid fuel supplied from the coal feeder 20 to the solid fuel pulverizing apparatus 100 increases or decreases in proportion to the increase or decrease of the load of the boiler 200, and the pulverizing ability of the solid fuel changes the rotation speed of the pulverizing table 12. It is supplied to the boiler 200 from the solid fuel pulverizer 100 by setting it as the target rotation speed command value Rta obtained by adding the addition rotation speed command value Rad to the reference rotation speed command value Rst or subtracting the subtraction rotation speed command value Rsu. To reduce the delay in timing of the increase or decrease in the amount of solid fuel supplied (ie, the delay in coal discharge or reduction of coal). Here, the initial value Rad0 of the additional rotation speed command value Rad calculated by the first calculation unit 53 when the load of the boiler 200 is increased from the first load L1 to the second load L2 is the first calculation unit 53 of the boiler 200 It is preferable to make it larger than initial value Rsu0 of subtraction rotation speed command value Rsu calculated when reducing 2nd load from 2nd load L2 to 1st load L1.

  This is to suppress the increase in thickness of the solid fuel layer between the grinding table 12 and the roller 13 in order to increase the grinding capacity of the solid fuel, the pressing force of the grinding table 12 and the roller 13 As the rotation speed of the grinding table 12 is increased with the increase, it takes time for the process of applying energy. On the other hand, in order to reduce the crushing ability of the solid fuel, it is a step of reducing the energy, and it takes less time than the step of adding energy in order for the state to transition smoothly.

  Further, it is desirable to set the initial value Rad0 to a value that is 1% or more and 30% or less of the reference rotation speed command value Rst. More preferably, it is 5% or more and 25% or less, and the initial value Rad0 is set larger than the initial value Rsu0. Further, it is desirable to set the initial value Rsu0 to a value of 1% or more and 30% or less of the reference rotation speed command value Rst. More preferably, it is 5% or more and 25% or less, and the initial value Rsu0 is set smaller than the initial value Rad0.

  Also, the initial value Rad0 and the initial value Rsu0 may take into consideration the amount of change in load per unit time (the boiler load change rate). That is, it is desirable to set the values of the initial value Rad0 and the initial value Rsu0 such that the load change rate is different according to the load range of the boiler 200. For example, when the boiler load is in the range of 30% or more and 90% or less, the boiler load change rate is in the range of the normally operated load change rate of 3% / min or more and 5% / min or less. It is desirable to set the values of the initial value Rad0 and the initial value Rsu0 so that the boiler load change rate decreases to, for example, 1% / min when the ratio is larger than%. The boiler load change rate is lowered when the boiler load is greater than 90% because the load change rate is high in the high load area, and the boiler load rises excessively beyond the upper limit load. In order to avoid becoming

  FIG. 5 is a diagram showing a time change of the amount of coal output from the solid fuel pulverizing device 100 to the boiler 200 when the boiler load is increased. In FIG. 5, a solid line indicates this embodiment, and indicates a time change of the amount of coal output when the control device 50 transmits the target rotation speed command value Rta to the drive unit 14. On the other hand, a broken line shows a comparative example of this embodiment, and shows a time change of the amount of coal output when the control device 50 transmits only the reference rotational speed command value Rst to the drive unit 14. The boiler load at time t1 is the first load L1, and at time t2, the boiler load is in a stable state by completing convergence on the second load L2.

  As shown in FIG. 5, in the present embodiment, the time taken for the amount of coal output to reach VL1 to VL2 is shorter than in the comparative example, and the responsiveness of the increase in the amount of coal output to the increase in the load of the boiler 200 is high. Further, in the present embodiment, the time taken for the boiler load to converge on VL2 which is the amount of coal output when the boiler load becomes the second load L2 is shorter than that of the comparative example, and the followability to the target load of the boiler load is high.

The operation and effects exerted by the solid fuel grinding device 100 of the present embodiment described above will be described.
According to solid fuel pulverizing apparatus 100 of the present embodiment, when a load command to increase the load of boiler 200 from first load L1 to second load L2 is input, addition rotational speed command to reference rotational speed command value Rst Since the initial value Rad0 larger than zero is given as the value Rad, the responsiveness of the increase in the rotational speed of the grinding table 12 to the load command can be enhanced. Moreover, since the addition rotation speed command value Rad gradually decreases from the initial value Rad0 to zero according to the increase in load, the rotational speed of the crushing table 12 is referenced when the load on the boiler becomes the second load L2. It is possible to set the speed according to the rotation speed command value Rst. Therefore, the load of the boiler 200 does not rise excessively beyond the target load, and the followability to the target load can be enhanced using the simple addition rotational speed command value Rad.

  Further, according to solid fuel pulverizing apparatus 100 of the present embodiment, when a load command for reducing the load of boiler 200 from second load L2 to first load L1 is input, rotation is subtracted from reference rotation speed command value Rst. Since the initial value Rsu0 greater than zero is given as the number command value Rsu, the responsiveness of the reduction of the rotational speed of the grinding table 12 to the load command can be enhanced. Further, since the subtraction rotation speed command value Rsu gradually decreases from the initial value Rsu0 to zero according to the reduction of the load, the rotational speed of the crushing table 12 is set when the load of the boiler 200 becomes the first load L1. It is possible to set the speed according to the reference rotational speed command value Rst. Therefore, the load of the boiler 200 does not decrease excessively beyond the target load, and the followability to the target load can be enhanced using the simple subtraction rotation speed command value Rsu.

Second Embodiment
Hereinafter, a second embodiment of the present disclosure will be described. The second embodiment is a modified example of the first embodiment, and except for the case particularly described below, is the same as the first embodiment, and the description thereof will be omitted.
The present embodiment differs from the first embodiment in that the solid fuel pulverizing device 100 sets the additional rotation speed command value Rad to zero when the load of the boiler 200 detected by the detection unit 52 is equal to or less than a predetermined load. FIG. 6 shows the relationship between the boiler load and the rotational speed command value in the case where the boiler load is increased from the predetermined load L0 lower than the first load L1 to the second load L2 in the solid fuel crushing apparatus 100 according to the second embodiment. FIG.

  The target rotation speed command value Rta shown in FIG. 6 is obtained by adding the additional rotation speed command value Rad calculated by the second calculation unit 54 to the reference rotation speed command value Rst calculated by the first calculation unit 53. The target rotational speed command value Rta shown by a solid line in FIG. 6 is the rotational speed with respect to the boiler load when a load command to increase the load up to the second load L2 is input while the detection unit 52 detects the predetermined load L0. It shows the change of the command value R.

  As shown in FIG. 6, when the load command is input in a state where the detection unit 52 detects the predetermined load L0, the second calculation unit 54 calculates zero as the additional rotation speed command value Rad. Therefore, in a load range lower than the first load L1 at a predetermined load L0 or more shown in FIG. 6, the target rotation speed command value Rta matches the reference rotation speed command value Rst. In this way, in the load range lower than the first load L1 (for example, the boiler load is about 30% to 40% load), it is difficult to generate coal delay and it is more than zero as the additional rotation speed command value Rad This is because it is not necessary to calculate a large value, and in the range where the boiler load is low, the additional rotation speed command value Rad is set to zero, the reference rotation speed command value Rst becomes excessive, and the rotation speed of the crushing table 12 excessively increases. Excessive increase in coal output is suppressed.

In addition, it is possible to control the delay (the coal output delay) of the timing at which the supply amount of solid fuel increases. The operation of the control device 50 in the load range from the first load L1 to the second load L2 is the same as that of the first embodiment.
Further, although not shown, also when the boiler load is reduced from the second load L2 to the predetermined load L0 lower than the first load L1 in the solid fuel pulverizing apparatus 100, the predetermined load lower than the first load L1 is similarly In the load range of L0 or more, zero is calculated as the subtraction rotation speed command value Rsu, and the target rotation speed command value Rta matches the reference rotation speed command value Rst.

Third Embodiment
Hereinafter, a third embodiment of the present disclosure will be described. The third embodiment is a modified example of the first embodiment, and except for the case particularly described below, is the same as the first embodiment, and the description thereof will be omitted.
In the present embodiment, when the load command to increase the load of the boiler 200 from the first load L1 to the third load L3 larger than the second load L2 is input, the additional rotation speed command value Rad is temporarily set in the second load L2. To be zero. FIG. 7 is a view showing the relationship between the boiler load and the rotational speed command value R when the boiler load is increased from the first load L1 to the third load L3 in the solid fuel crushing apparatus 100 according to the present embodiment.

  Further, in the present embodiment, when a load command to reduce the load of the boiler 200 from the third load L3 to the first load L1 is input, the subtraction rotational speed command value Rsu is once set to zero at the second load L2. It is to FIG. 8 is a view showing the relationship between the boiler load and the rotational speed command value R when reducing the boiler load from the third load L3 to the first load L1 in the solid fuel pulverizing apparatus 100 according to the present embodiment.

Here, an operation of the control device 50 when a load command to increase the load of the boiler 200 from the first load L1 to the third load L3 larger than the second load L2 will be described.
The target rotation speed command value Rta shown in FIG. 7 is obtained by adding the additional rotation speed command value Rad calculated by the second calculation unit 54 to the reference rotation speed command value Rst calculated by the first calculation unit 53. The target rotation speed command value Rta shown by a solid line in FIG. 7 is a rotation with respect to the boiler load when a load command for increasing the load to the third load L3 is input in a state where the detection unit 52 detects the first load L1. It shows the change of the number command value R.

  As shown in FIG. 7, when a load command is input in a state where the detection unit 52 detects the first load L1, the second calculation unit 54 calculates an initial value Rad0 as the addition rotation speed command value Rad. , To the control unit 51. The control unit 51 adds the initial value Rad0 to the reference rotation speed command value Rst1 at the first load L1 calculated by the first calculation unit 53 to calculate the rotation speed command value Rta1. The rotation speed command value Rta1 becomes the target rotation speed command value Rta for the first load L1.

  As shown in FIG. 7, the target rotational speed command value Rta increases in proportion to the boiler load until the boiler load reaches from the first load L1 to the second load L2, and the target rotational speed command value Rta at the second load L2 Coincides with the reference rotational speed command value Rst. This is because the addition rotational speed command value Rad calculated by the second calculation unit 54 at the second load L2 is zero. Thus, the second calculation unit 54 calculates the additional rotation speed command value Rad so as to gradually decrease from the initial value Rad0 to zero according to the increase in the load of the boiler 200.

  Further, as shown in FIG. 7, when the detection unit 52 detects the second load L2, the second calculation unit 54 calculates an initial value Rad0 as the additional rotation speed command value Rad, and transmits the initial value Rad0 to the control unit 51. The control unit 51 adds the initial value Rad0 to the reference rotation speed command value Rst2 at the second load L2 calculated by the first calculation unit 53, to calculate the rotation speed command value Rta2. The rotation speed command value Rta2 becomes the target rotation speed command value Rta for the second load L2.

  As shown in FIG. 7, the target rotation speed command value Rta increases in proportion to the boiler load from the second load L2 to the third load L3 until the boiler load reaches the second load L2, and the target rotation speed command value Rta at the third load L3 Coincides with the reference rotational speed command value Rst. This is because the addition rotational speed command value Rad calculated by the second calculator 54 at the third load L3 is zero. Thus, the second calculation unit 54 calculates the additional rotation speed command value Rad so as to gradually decrease from the initial value Rad0 to zero according to the increase in the load of the boiler 200.

Next, an operation of the control device 50 when a load command to reduce the load of the boiler 200 from the third load L3 to the first load L1 smaller than the second load L2 is input will be described.
As shown in FIG. 8, when a load command to reduce the boiler load to the first load L1 is input while the detection unit 52 is detecting the third load L3, the second calculation unit 54 calculates the subtraction rotational speed An initial value Rsu0 is calculated as the command value Rsu, and transmitted to the control unit 51. The control unit 51 subtracts the initial value Rsu0 from the reference rotation speed command value Rst3 at the third load L3 calculated by the first calculation unit 53 to calculate the rotation speed command value Rta3. The rotation speed command value Rta3 becomes the target rotation speed command value Rta for the third load L3.

  As shown in FIG. 8, the target rotational speed command value Rta decreases in proportion to the boiler load until the boiler load reaches from the third load L3 to the second load L2, and the target rotational speed command value Rta at the second load L2 Coincides with the reference rotational speed command value Rst. This is because the subtraction rotation speed command value Rsu calculated by the second calculation unit 54 at the second load L2 is zero. As described above, the second calculation unit 54 calculates the subtraction rotation speed command value Rsu so as to gradually decrease from the initial value Rsu0 to zero from the initial value Rsu0 according to the decrease in the load of the boiler 200.

  Further, as shown in FIG. 8, when the detection unit 52 detects the second load L2, the second calculation unit 54 calculates an initial value Rsu0 as the subtraction rotation speed command value Rsu, and transmits it to the control unit 51. The control unit 51 subtracts the initial value Rsu0 from the reference rotation speed command value Rst2 at the second load L2 calculated by the first calculation unit 53 to calculate the rotation speed command value Rta2. The rotation speed command value Rta2 becomes the target rotation speed command value Rta for the second load L2.

  As shown in FIG. 8, the target rotational speed command value Rta decreases in proportion to the boiler load until the boiler load reaches from the second load L2 to the first load L1, and at the first load L1, the target rotational speed command value Rta Coincides with the reference rotational speed command value Rst. This is because the subtraction rotation speed command value Rsu calculated by the second calculation unit 54 at the first load L1 is zero. As described above, the second calculation unit 54 calculates the subtraction rotation speed command value Rsu so as to gradually decrease from the initial value Rsu0 to zero from the initial value Rsu0 according to the decrease in the load of the boiler 200.

  According to the embodiment described above, when the load of the boiler 200 is increased from the first load L1 to the third load L3 larger than the second load L2, the additional rotation speed command value Rad is zero at the second load L2 Therefore, the number of rotations of the grinding table 12 is prevented from being excessively increased as compared to the case where the addition rotation number command value Rad is maintained at a value larger than zero from the first load L1 to the third load L3. . Therefore, excessive increase in the amount of coal output with an increase in the rotation speed of the grinding table 12 is suppressed.

  Further, according to the present embodiment, when reducing the load of the boiler 200 from the third load L3 larger than the second load L2 to the first load L1, the subtraction rotational speed command value Rsu is zero at the second load L2. Therefore, the number of revolutions of the grinding table 12 is prevented from being excessively reduced as compared with the case where the subtraction rotational speed command value Rsu is maintained at a value larger than zero from the third load L3 to the first load L1. Therefore, excessive decrease in the amount of coal output with the decrease in the rotation speed of the grinding table 12 is suppressed.

Fourth Embodiment
Hereinafter, a fourth embodiment of the present disclosure will be described. The fourth embodiment is a modification of the first embodiment, and is the same as the first embodiment except the case described below in particular, and the description thereof will be omitted.
In the first embodiment, the initial value Rad0 of the addition rotational speed command value Rad and the initial value Rsu0 of the subtraction rotational speed command value Rsu are set to constant values regardless of the boiler load range, or in the boiler load range. The values were set accordingly.

  On the other hand, in the present embodiment, the initial value Rad0 and the initial value Rsu0 are set as a function of the load change amount (boiler change rate) of the boiler 200 per unit time. FIG. 9 is a view showing the relationship between the boiler load change rate and the initial value Rad0 of the addition rotational speed command value Rad and the initial value Rsu0 of the subtraction rotational speed command value Rsu in the solid fuel crushing apparatus 100 according to the fourth embodiment. .

  As shown in FIG. 9, the initial value Rad0 of the addition rotation speed command value Rad is set by a linear function that increases in proportion to the increase in the boiler load change rate. That is, when the load command to increase the load of the boiler 200 is input, the second calculation unit 54 sets the initial value Rad0 according to the amount of increase of the load of the boiler 200 per unit time. By setting the initial value Rad0 in accordance with the amount of increase in load per unit time, the appropriate initial value Rad0 in accordance with the amount of increase in load per unit time can be set using a simple linear function. It is possible to suppress an excessive increase in the amount of carbon output due to an excessive increase in the rotation speed of the crushing table 12 while enhancing the followability of the rotation speed of the crushing table 12 to the change in load.

Further, the initial value Rsu0 of the subtraction rotational speed command value Rsu is set by a linear function that increases in proportion to the increase in the boiler load change rate. That is, when a load command to reduce the load on the boiler 200 is input, the second calculation unit 54 sets an initial value Rsu0 according to the amount of decrease on the load on the boiler 200 per unit time. By setting the initial value Rsu0 according to the amount of decrease in load per unit time, an appropriate initial value Rsu0 according to the amount of decrease in load per unit time can be set using a simple linear function, and It is possible to suppress an excessive decrease in the amount of carbon output due to an excessive decrease in the rotational speed of the crushing table 12 while enhancing the followability of the rotational speed of the crushing table 12 to the change in load.
As described in the first embodiment, when the increase and decrease of the boiler load are changed at the same boiler load change rate, the initial value Rad0 is preferably made larger than the initial value Rsu0.

DESCRIPTION OF REFERENCE NUMERALS 10 mill 11 housing 12 crushing table 13 roller 14 drive unit 15 drive shaft 16 classification unit 17 fuel supply unit 18 motor 19 outlet 20 feeder 20 blower 30a heat gas blower 30b cold gas blower 30c heat gas damper 30d cold gas damper 40 temperature detection Unit 50 Controller 51 Control unit 52 Detection unit 53 First calculation unit 54 Second calculation unit 100 Solid fuel pulverizing device 100a Primary air flow passage 100b Supply flow passage 200 Boiler 210 Fire furnace 220 Burner unit L1, L2 Boiler load R Speed command Value Rad Add rotation speed command value Rad0 Initial value Rst Reference rotation speed command value Rsu Subtraction rotation speed command value Rsu0 Initial value Rta Target rotation speed command value

Claims (9)

A solid fuel pulverizing apparatus for pulverizing solid fuel and supplying it to a boiler, comprising:
Grinding table,
A driving unit that generates a driving force for rotating the crushing table;
A roller for grinding the solid fuel supplied from the fuel supply unit to the grinding table with the grinding table;
A classification unit for classifying the solid fuel pulverized by the roller into fine pulverized fuel smaller than a predetermined particle size and carrying it out of the solid fuel pulverizing apparatus;
A first calculation unit that calculates a reference rotation speed command value of the crushing table according to the load of the boiler;
A second calculation unit that calculates an additional rotation speed command value of the crushing table according to the load;
A control unit configured to control the number of rotations of the crushing table driven by the drive unit based on a target rotation number command value obtained by adding the additional rotation number command value to the reference rotation number command value;
When the load command to increase the load of the boiler from the first load to the second load is input, the second calculation unit changes the additional rotation speed command value from the initial value to zero according to the increase of the load. Solid fuel pulverizer to reduce gradually until all.   When a load command to increase the load of the boiler from the first load to a third load that is larger than the second load is input, the second calculation unit is configured to transmit the load from the first load to the second load. The addition rotation number command value is gradually decreased from the initial value to zero according to the increase, and the addition rotation number command value is zeroed from the initial value according to the increase from the second load to the third load. The solid fuel comminution device according to claim 1, wherein the solid fuel comminution device is gradually reduced to   The solid fuel grinding device according to claim 1 or 2, wherein the second calculation unit sets the initial value in accordance with an increase amount of the load per unit time.   The solid fuel grinding device according to claim 1 or 2, wherein the second calculation unit sets the additional rotation speed command value to zero when the load is lower than a predetermined load. The second calculation unit calculates a subtraction rotation speed command value of the crushing table according to the load,
When a load command to reduce the load of the boiler from the second load to the first load is input, the second calculation unit sets the subtraction rotational speed command value to the initial value according to the decrease of the load. The solid fuel comminution device according to any one of claims 1 to 4, wherein it gradually decreases from zero to zero.   When a load command to reduce the load of the boiler from the third load, which is larger than the second load, to the first load is input, the second calculation unit is configured to send the third load to the second load. The subtraction rotational speed command value is gradually decreased from the initial value to zero according to the reduction, and the subtraction rotational speed command value is zeroed from the initial value according to the reduction from the second load to the first load. The solid fuel comminution device according to claim 5, wherein the amount is gradually reduced to   The solid fuel comminution device according to claim 5 or 6, wherein the second calculation unit sets the initial value in accordance with the decrease amount of the load per unit time. A control method of a solid fuel pulverizing apparatus for pulverizing solid fuel and supplying it to a boiler, comprising:
The solid fuel pulverizing apparatus pulverizes the solid fuel supplied from the fuel supply unit to the pulverizing table between the pulverizing table, the driving unit generating a driving force for rotating the pulverizing table, and the pulverizing table. A roller, and a classification unit for classifying the solid fuel pulverized by the roller into fine fuel particles smaller than a predetermined particle size and discharging the classified fuel from the solid fuel pulverizing device;
A first calculation step of calculating a reference rotation speed command value of the crushing table according to the load of the boiler;
A second calculation step of calculating an additional rotation speed command value of the crushing table according to the load;
A control step of controlling the number of rotations of the grinding table driven by the drive unit based on a target rotation number command value obtained by adding the additional rotation number command value to the reference rotation number command value;
When the load command to increase the load of the boiler from the first load to the second load is input, the second calculation step changes the additional rotation speed command value from the initial value to zero according to the increase of the load. The control method of the solid fuel pulverizer which reduces gradually until all. And a third calculation step of calculating a subtraction rotation speed command value corresponding to the load,
When a load command to reduce the load of the boiler from the second load to the first load is input, the third calculation step makes the subtraction rotational speed command value zero from the initial value according to the decrease of the load The control method of the solid fuel pulverization device according to claim 8, wherein it gradually reduces to.

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