JP2017136540A - Solid fuel pulverizing apparatus and control method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the trouble that unpulverized solid fuel accumulates in a large amount in the bottom of a housing in which a rotary table, a roller, and a classification part are housed.SOLUTION: A solid fuel pulverizing apparatus 100 is provided that comprises a rotary table 12, a coal feeder 20, a roller 13, an energization mechanism 15, a rotary classification part 16, an air blowing part 30, a housing 11, a load cell 19 that detects an accumulation amount of unpulverized solid fuel accumulated in the bottom of the housing 11, and a controlling part 40. The controlling part 40, when an increment in the accumulation amount to the supply amount of the solid fuel by the coal feeder 20 exceeds a predetermined limit value, performs at least either one of a first control mode of increasing an energization force by the energization mechanism 15 and a second control mode of decreasing the number of revolutions of the classification part 16.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solid fuel pulverization apparatus and a control method thereof.

2. Description of the Related Art Conventionally, a vertical roller mill is known that pulverizes a solid fuel such as coal charged on a pulverizing table between a pulverizing table and a pulverizing roller (for example, see Patent Document 1).
The vertical roller mill disclosed in Patent Document 1 detects a pressure gradient of the pressure in the mill in order to avoid overload operation due to an increase in the amount of coal retained in the mill, and the rotational speed of the classifier based on this pressure gradient. Is corrected. According to the vertical roller mill disclosed in Patent Document 1, when the overload operation state is determined, the rotation speed of the classifier is temporarily reduced, thereby increasing the amount of coal output from the classifier. Load operation can be eliminated.

Japanese Patent No. 3964602

In Patent Document 1, an overload operation state is determined when the detected value of the pressure gradient exceeds a threshold value. However, when the detected value of the pressure gradient is equal to or less than the threshold value, the overload operation state is not detected. to decide.
However, even when the detected value of the pressure gradient is less than or equal to the threshold value, the amount of coal retained in the mill is large and unground solid fuel falls from the pulverization table and accumulates. Unground solid fuel may accumulate. In this case, since it is determined that the engine is not in an overload operation state, a state in which the amount of coal retained in the mill is not solved, and a large amount of unpulverized solid fuel accumulates below the housing. In particular, the unpulverized solid fuel that has fallen from the pulverization table does not return to the pulverization table again, and thus cannot be used as fuel and is wasted.

  The present invention has been made in view of such circumstances, and a solid fuel that suppresses a problem that a large amount of unground solid fuel accumulates below a housing that houses therein a rotary table, a roller, and a classification unit. An object of the present invention is to provide a pulverizing apparatus and a control method thereof.

In order to achieve the above object, the present invention employs the following means.
The solid fuel pulverization apparatus according to one aspect of the present invention pulverizes the solid fuel on the rotary table, a rotary table that is rotated by a driving force from a driving unit, a fuel supply unit that supplies the rotary table with the solid fuel. A roller, an urging mechanism that generates an urging force that presses the roller against the rotary table, and the solid fuel that is provided above the rotary table and crushed by the roller is classified into finely pulverized fuel smaller than a predetermined particle size. A rotary classifying unit, an air blowing unit for blowing an oxidizing gas for guiding the solid fuel crushed by the roller to the classifying unit, the rotary table, the roller, and the classifying unit are accommodated therein. A housing, a detection unit for detecting an accumulation amount of the unpulverized solid fuel accumulated below the housing, the urging force and the distribution by the urging mechanism; A control unit that controls the number of rotations of the unit, and the control unit includes a biasing mechanism when an increase amount of the accumulated amount with respect to the solid fuel supply amount by the fuel supply unit exceeds a predetermined limit value. At least one of a first control mode for increasing the urging force and a second control mode for decreasing the rotation speed of the classifying unit.

According to the solid fuel pulverization apparatus of one aspect of the present invention, the detection unit detects the accumulation amount of the unpulverized solid fuel accumulated below the housing, and the accumulation amount increases with respect to the solid fuel supply amount by the fuel supply unit. When the amount exceeds the predetermined limit value, at least one of the first control mode for increasing the urging force by the urging mechanism and the second control mode for decreasing the rotation speed of the classifying unit is executed. Therefore, when the first control mode is executed, the solid fuel is pulverized by the roller and the rotary table as the urging force is increased by the urging mechanism. As the pulverization of the solid fuel is promoted, the pulverized fuel supplied from the classification unit to the outside increases, and the increase in the amount of unground pulverized solid fuel accumulated below the housing is suppressed. In addition, when the second control mode is executed, the fine fuel supplied from the classification unit to the outside increases as the rotation speed of the classification unit decreases, and the accumulation of unground solid fuel accumulated below the housing Increase in volume is suppressed.
As described above, according to the solid fuel pulverization apparatus of one aspect of the present invention, it is possible to suppress a problem that a large amount of unpulverized solid fuel accumulates below the housing that houses the rotary table, the roller, and the classification unit. Can do.

In the solid fuel pulverization apparatus according to the aspect of the present invention, the control unit executes the pre-first control mode when the increase amount with respect to the supply amount exceeds the predetermined limit value, and executes the first control mode. Alternatively, the second control mode may be executed when the increase amount with respect to the supply amount exceeds the predetermined limit value.
In this way, the first control mode that does not lower the classification performance of the fine fuel is executed preferentially over the second control mode, so that the fine fuel classification performance is not reduced and is not crushed below the housing. The problem that a large amount of solid fuel accumulates can be suppressed. In addition, even if the first control mode is executed, if the increase amount with respect to the supply amount exceeds a predetermined limit value, the second control mode is executed, so that a large amount of unground solid fuel accumulates below the housing. Can be reliably suppressed.
Here, the first control mode is prioritized over the second control mode because the performance of the solid fuel crusher is reduced when the classification performance of the pulverized fuel is decreased but when the urging force is increased by the urging mechanism. This is because the adverse effect on performance is large.

In the solid fuel pulverization apparatus having the above-described configuration, the control unit is configured to supply the oxidizing gas by the blowing unit when the increase amount with respect to the supply amount exceeds the predetermined limit value even when the second control mode is executed. The aspect which performs the 3rd control mode which increases an air volume may be sufficient.
In this way, the second control mode that does not increase the excess ratio of the oxidizing gas is executed preferentially over the third control mode. A problem that a large amount of unground solid fuel accumulates can be suppressed. In addition, even if the second control mode is executed, the third control mode is executed when the increase amount with respect to the supply amount exceeds the predetermined limit value, so that a large amount of uncrushed solid fuel accumulates below the housing. Can be reliably suppressed.
Here, the second control mode is prioritized over the third control mode because increasing the excess ratio of the oxidizing gas reduces the operation of the solid fuel pulverizer rather than lowering the classification performance of the pulverized fuel. This is because the adverse effect on performance is large.

In the solid fuel pulverization apparatus according to the aspect described above, the control unit supplies the solid fuel by the fuel supply unit when the increase amount with respect to the supply amount exceeds the predetermined limit value even after executing the third control mode. A fourth control mode for decreasing the amount may be executed.
By doing so, the third control mode that does not reduce the amount of solid fuel supplied by the fuel supply unit is executed preferentially over the fourth control mode, so the amount of solid fuel supplied by the fuel supply unit is reduced. Therefore, the problem that a large amount of unpulverized solid fuel accumulates below the housing can be suppressed. In addition, even if the third control mode is executed, if the increase amount with respect to the supply amount exceeds the predetermined limit value, the fourth control mode is executed, so that a large amount of uncrushed solid fuel accumulates below the housing. Can be reliably suppressed.
Here, the third control mode is prioritized over the fourth control mode because the amount of solid fuel supplied by the fuel supply unit is decreased rather than the excess ratio of oxidizing gas is increased. This is because the adverse effect on the operation performance of the pulverizer is great.

In the solid fuel pulverization apparatus according to one aspect of the present invention, the detection unit may detect an accumulated amount of the unground crushed solid fuel that has dropped onto the bottom of the housing.
In this way, the accumulated amount of unground solid fuel that does not fall back to the bottom of the housing and return to the turntable is directly detected, and a large amount of unground solid fuel accumulates at the bottom of the housing. Problems can be suppressed.

In the solid fuel pulverization apparatus according to one aspect of the present invention, the detection unit may detect an accumulated amount of the unpulverized solid fuel accumulated on the rotary table.
By doing in this way, it is possible to detect in advance that such a problem may occur before the problem that unground solid fuel falls to the bottom of the housing and accumulates in large quantities occurs. it can.

  The control method of the solid fuel crusher of one aspect of the present invention includes a rotary table that rotates by a driving force from a drive unit, a fuel supply unit that supplies solid fuel to the rotary table, and the solid fuel on the rotary table. A pulverizing roller, an urging mechanism for generating an urging force for pressing the roller against the rotary table, and the solid fuel crushed by the roller provided above the rotary table into fine pulverized fuel smaller than a predetermined particle size. A rotary classifying unit, an air blowing unit for blowing an oxidizing gas for guiding the solid fuel crushed by the roller to the classifying unit, and the rotary table, the roller, and the classifying unit. And a solid fuel supply device control method comprising: a housing for detecting uncollected solid fuel accumulation amount accumulated below the housing A first control step of increasing the urging force by the urging mechanism when the increase amount of the accumulated amount with respect to the supply amount of the solid fuel by the fuel supply unit exceeds a predetermined limit value, and the supply amount And a second control step of reducing the rotational speed of the classifying unit when the amount of increase with respect to exceeds the predetermined limit value.

  According to the control method of the solid fuel pulverization apparatus of one aspect of the present invention, it is possible to suppress a problem that a large amount of unground pulverized fuel accumulates below the housing that houses the rotary table, the roller, and the classification unit. it can.

  According to the present invention, it is possible to provide a solid fuel pulverization apparatus and a control method therefor, in which a problem that a large amount of unground pulverized solid fuel accumulates below a housing that houses a rotary table, a roller, and a classification unit is suppressed. it can.

It is a lineblock diagram showing the solid fuel crusher and boiler of a 1st embodiment. It is a longitudinal cross-sectional view of the urging mechanism shown in FIG. It is a flowchart which shows the 1st control mode which a control part performs. It is a flowchart which shows the 2nd control mode which a control part performs. It is a flowchart which shows the 3rd control mode which a control part performs. It is a flowchart which shows the 4th control mode which a control part performs. It is a figure which shows the relationship between the supply amount of a solid fuel, and the increase amount of the unground solid fuel with respect to the supply amount of a solid fuel. It is a block diagram which shows the solid fuel grinding | pulverization apparatus and boiler of 2nd Embodiment.

[First Embodiment]
Hereinafter, a solid fuel crusher 100 and a control method thereof according to a first embodiment of the present invention will be described with reference to the drawings.
The solid fuel pulverization apparatus 100 according to the present embodiment includes a vertical roller mill 10 that pulverizes solid fuel to produce finely divided fuel, a coal feeder 20 (fuel supply unit) that supplies the solid fuel to the vertical roller mill 10, A blower 30 that blows air (oxidizing gas) to the mold roller mill 10 and a controller 40 that controls each part of the solid fuel crusher 100 are provided.
Here, the solid fuel is a solid carbonaceous fuel such as coal. Further, for example, biomass that is a biological organic substance such as wood pellets may be used as the solid fuel.

  Hereinafter, a description will be given of a boiler 200 that generates steam by performing combustion using each part constituting the solid fuel pulverizer 100 and fine fuel supplied from the solid fuel pulverizer 100.

  As shown in FIG. 1, the vertical roller mill 10 includes a substantially cylindrical hollow housing 11, a rotary table 12, a roller 13 for pulverizing solid fuel on the rotary table 12, and a drive unit that rotates the rotary table 12. 14 and an urging mechanism 15.

  Further, the vertical roller mill 10 includes a rotary classification unit 16 disposed at an upper portion in the housing 11, and a solid fuel input unit 17 that supplies solid fuel supplied from the coal feeder 20 to the center of the rotary table 12. A recovery unit 18 that recovers unground solid fuel that has fallen to the bottom 11a of the housing 11 and a load cell 19 that detects the load of the recovery unit 18 are provided.

  Here, the unpulverized solid fuel is not only pulverized but supplied to the bottom table 11a of the housing 11 without being pulverized, but is pulverized on the rotary table 12. It is assumed that those that fall to the bottom part 11a of the housing 11 without being guided to the classifying part 16 are included.

  The housing 11 accommodates each part of the vertical roller mill 10 including the rotary table 12, the roller 13, and a classification part 16 described later. The lower end portion of the housing 11 communicates with the flow path 50, and primary air (primary oxidizing gas) flows from the flow path 50 into the lower end portion of the housing 11.

  The turntable 12 is a disk-like member that is disposed in the lower part of the housing 11 and is attached so as to be rotatable around an axis extending in the vertical direction. The rotary table 12 rotates around the axis by a driving force from a driving unit 14 described later.

  At a plurality of locations outside the turntable 12, there are provided oxidizing gas outlets (not shown) through which primary air flowing from the flow path 50 flows out into the space above the turntable 12 in the housing 11. A vane (not shown) is installed above the oxidizing gas outlet, and the vane gives a turning force to the primary air blown out from the oxidizing gas outlet. The primary air to which the turning force is given by the vanes becomes an air flow having a turning speed component, and guides the solid fuel crushed on the rotary table 12 to the classification unit 16 above the housing 11. Of the pulverized solid fuel mixed with the primary air, the pulverized product with a large particle size falls without reaching the classification unit 16 and is returned to the turntable 12 again.

The roller 13 is a device that is pressed against the outer periphery of the turntable 12 and crushes the solid fuel on the turntable 12. The roller 13 is pressed against the outer peripheral portion of the rotary table 12 by a biasing force from a biasing mechanism 15 described later.
In FIG. 1, only one roller 13 is shown, but a plurality of rollers 13 are arranged at regular intervals in the circumferential direction so as to press the outer peripheral portion of the rotary table 12. For example, three rollers 13 are arranged on the outer peripheral portion with an angular interval of 120 °. In this case, the portion where the three rollers 13 are in contact with the outer peripheral portion of the turntable 12 (the portion to be pressed) is equidistant from the center of the turntable 12.

  The drive unit 14 is a device that generates a drive force that rotates the rotary table 12 about an axis extending in the vertical direction. The driving force generated by the drive unit 14 is transmitted to the rotary table 12 installed inside the housing 11 via the drive shaft.

  The urging mechanism 15 is a mechanism that generates an urging force that presses the roller 13 against the rotary table 12. As shown in FIG. 2, the urging mechanism 15 includes a rotating shaft 15a to which the roller 13 is attached, a main body 15b that holds the rotating shaft 15a, a support shaft 15c that is fixedly attached to a side portion of the main body 15b, and a main body. An arm 15d attached so as to extend upward on the upper surface of 15b, a protrusion 15e provided so as to protrude on the lower surface of the main body 15b, and a load applying portion 15f that presses the upper end of the arm 15d. Prepare.

  In the urging mechanism 15, the load applying portion 15f operated by power from a hydraulic mechanism (not shown) presses the upper end portion of the arm 15d, thereby swinging the arm 15d around the support shaft 15c. As the arm 15d swings around the support shaft 15c, the roller 13 is given an urging force in a direction in which it is pressed against the rotary table 12.

  The classification unit 16 is a rotary classifier that is provided above the rotary table 12 and classifies the solid fuel pulverized by the roller 13 into a finely divided fuel having a predetermined particle diameter. The classifying unit 16 includes a blade that rotates about the cylindrical axis of the substantially cylindrical housing 11. The pulverized product of the solid fuel that has reached the classification unit 16 has only a fine fuel smaller than a predetermined particle size flow into the blade due to the relative balance between the centrifugal force and centripetal force generated by the rotating blade and the flow of primary air. It flows out from the outlet 16b. The outlet 16 b communicates with the supply channel 60. The blades of the classification unit 16 are given a driving force by the motor 16 a and rotate around the cylindrical axis of the housing 11. The rotation of the motor 16a is controlled by an instruction from the control unit 40.

  The solid fuel input unit 17 is a member formed in a cylindrical shape so as to supply the solid fuel supplied from the coal feeder 20 to the center of the rotary table 12. The solid fuel input unit 17 is attached so as to penetrate the upper end of the housing 11, and drops the solid fuel input from the top toward the center of the turntable 12.

  The recovery unit 18 is a sealed container formed in a cylindrical shape that recovers unground crushed solid fuel that has dropped onto the bottom 11 a of the housing 11. The unpulverized solid fuel that has fallen to the bottom 11a of the housing 11 is guided to the recovery unit 18 through a recovery duct 18a from a recovery hole 11b formed in the bottom 11a. The collection rod 12 a attached to the rotary table 12 rotates around the axis together with the rotary table 12. The recovery rod 12a scrapes and collects the unpulverized solid fuel that has fallen to the bottom 11a and guides it to the recovery hole 11b.

  The load cell (load detection unit) 19 is a device that detects the load of the collection unit 18 as a load signal that is an electrical signal and transmits the load signal to the control unit 40. Based on the difference between the first load signal obtained at the predetermined first timing and the second load signal obtained at the predetermined second timing, the control unit 40 causes the recovery unit 18 to perform the recovery from the first timing to the second timing. The accumulated weight of the recovered unground solid fuel can be obtained.

  Since the load cell 19 is a device that detects the load of the recovery unit 18, if the recovery unit 18 is vibrated by the operation of the rotary table 12 or the like, the load signal fluctuates due to the vibration. Therefore, it is desirable to provide a vibration preventing mechanism (not shown) for preventing vibration transmission from the collection unit 18 to the load cell 19 at a portion where the collection unit 18 is connected to the load cell 19.

  In the present embodiment, the load cell 19 is used to detect the accumulation amount of the unpulverized solid fuel recovered by the recovery unit 18, but other modes may be used. For example, a level meter (not shown) for detecting the height of the upper end surface of the unground solid fuel recovered by the recovery unit 18 may be provided inside the recovery unit 18. In this case, the level meter transmits a level signal indicating the accumulation amount of the unpulverized solid fuel recovered by the recovery unit 18 to the control unit 40 inside the recovery unit 18. Based on the difference between the first level signal obtained at the predetermined first timing and the second level signal obtained at the predetermined second timing, the control unit 40 causes the recovery unit 18 to perform the recovery from the first timing to the second timing. The accumulated amount of recovered unground solid fuel can be obtained.

  The coal feeder 20 is a device that supplies solid fuel to the center of the rotary table 12 via the solid fuel input unit 17 of the vertical roller mill 10. The coal feeder 20 includes a hopper 21, a transport unit 22, and a motor 23. The transport unit 22 transports the solid fuel discharged from the lower end portion of the hopper 21 by the driving force applied from the motor 23 and guides it to the solid fuel input unit 17 of the vertical roller mill 10. The controller 40 can control the speed at which the transport unit 22 transports the solid fuel by adjusting the rotational speed command to the motor 23. The amount (supply amount A1) of the solid fuel supplied per unit time to the vertical roller mill 10 is proportional to the speed at which the transport unit 22 transports the solid fuel. Therefore, the control unit 40 can control the supply amount A1 of the solid fuel to the turntable 12 by controlling the speed at which the transport unit 22 transports the solid fuel.

  The air blowing unit 30 is a device that blows primary air for guiding the solid fuel crushed by the roller 13 to the classifying unit 16. The air blower 30 includes a hot gas blower 30a and a cold gas blower 30b. The hot gas blower 30a is a blower that sucks and blows in a hot gas (first oxidizing gas) supplied from a heat exchanger. The cold gas blower 30b is a blower that sucks and blows cold gas (second oxidizing gas) that is ambient temperature outside air. The air flow rate of the hot gas blower 30a and the air flow rate of the cold gas blower 30b are controlled by control signals from the control unit 40, respectively.

The control unit 40 is a device that controls each part of the solid fuel crusher 100.
Here, the control unit 40 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program as an example, and the CPU reads the program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized.
Specific processing executed by the control unit 40 will be described later.

Next, a description will be given of the boiler 200 that performs combustion using the pulverized fuel supplied from the solid fuel crusher 100 to generate steam.
The boiler 200 includes a furnace 210, a burner unit 220, and an economizer 230.

  The burner unit 220 is a device that burns the pulverized fuel using primary air containing the pulverized fuel supplied from the supply flow path 60 and secondary air supplied from a heat exchanger (not shown). The combustion of the pulverized fuel is performed in the furnace 210, and the high-temperature combustion gas is discharged to the outside of the boiler 200 after passing through the economizer 230.

  The combustion gas discharged from the boiler 200 is sent to a heat exchanger (not shown), and heat exchange with the outside air is performed. The outside air heated by heat exchange with the combustion gas in the heat exchanger is sent to the above-described hot gas blower 30a. The water heated in the economizer 230 is further heated by an evaporator (not shown) and a superheater (not shown) to become steam and sent to a steam turbine (not shown).

  The combustion gas before being discharged from the boiler 200 is extracted on the upstream side of the economizer 230 and sent to the regulating valve 240. Further, the combustion gas before being discharged from the boiler 200 is extracted on the downstream side of the economizer 230 and sent to the regulating valve 250.

  The flow rate of the combustion gas extracted on the upstream side and the downstream side of the economizer 230 is adjusted by the control unit 40 controlling the opening degree of the regulating valve 240 and the regulating valve 250. The combustion gas that has passed through the regulating valve 240 and the regulating valve 250 is sent to the cyclone 260. The cyclone 260 removes particulate matter contained in the combustion gas and sends the combustion gas to the regulating valve 270. And the combustion gas of the flow volume according to the opening degree of the regulating valve 270 is sent to the hot gas blower 30a.

The control unit 40 adjusts the flow rate of the combustion gas extracted on the upstream side of the economizer 230 and the flow rate of the combustion gas extracted on the downstream side of the economizer 230, thereby adjusting the temperature of the combustion gas sent to the cyclone 260. Can be adjusted.
Moreover, the control part 40 can adjust the flow volume of the high temperature combustion gas mixed in the external air heated by the heat exchanger (not shown) by controlling the opening degree of the adjustment valve 270.

Next, a process performed by the control unit 40 of the present embodiment to suppress a problem that a large amount of unground solid fuel accumulates in the bottom 11a of the housing 11 will be described with reference to FIGS.
The control unit 40 executes each process shown in FIG. 3 to FIG. 6 from the start to the end, and when the process is ended, starts the process again and repeats the execution of each process.

In each process shown in FIGS. 3 to 6, the control unit 40 is based on the solid fuel supply amount A1 by the coal feeder 20 and the unpulverized solid fuel increase amount A2 accumulated in the bottom 11a of the housing 11. When A2 / A1 exceeds the predetermined limit value Lv, the first control mode, the second control mode, the third control mode, and the fourth control mode are executed in this order.
Here, the case where A2 / A1 exceeds the predetermined limit value Lv refers to the case where the ratio of the increase amount A2 of the unpulverized solid fuel to the supply amount A1 of the solid fuel by the coal feeder 20 is large. Various values can be adopted as the predetermined limit value Lv, and for example, it can be 0.01%.

  In the first control mode, the second control mode, the third control mode, and the fourth control mode, the pulverized fuel supplied to the outside from the vertical roller mill 10 is increased, and the unpulverized fuel accumulated in the bottom portion 11a of the housing 11 is increased. A process for suppressing an increase in the amount of accumulated solid fuel is executed.

  The first control mode is a control mode in which the urging force of the roller 13 by the urging mechanism 15 is increased. The second control mode is a control mode for reducing the rotation speed of the classifying unit 16. The third control mode is a control mode in which the amount of primary air blown by the blower 30 is increased. The fourth control mode is a control mode in which the solid fuel supply amount A1 by the coal feeder 20 is decreased.

By executing each control mode, it is possible to suppress an increase in the amount of unground pulverized solid fuel accumulated in the bottom 11a of the housing 11. On the other hand, by executing each control mode, an adverse effect on the operation performance of the solid fuel crusher 100 also occurs.
In the first control mode, an increase in power accompanying an increase in the biasing force occurs. In the second control mode, the classification performance of the pulverized fuel is deteriorated. In the third control mode, the excess ratio of primary air increases. In the fourth control mode, the supply amount A1 of the pulverized fuel supplied to the boiler 200 decreases.

  The priority is increased in the order of the first control mode, the second control mode, the third control mode, and the fourth control mode. The reason why the second control mode has an adverse effect on the driving performance than the first control mode is. This is because the third control mode has a larger adverse effect on the driving performance than the second control mode, and the fourth control mode has a larger adverse effect on the driving performance than the third control mode.

Hereinafter, the detail of the process which the control part 40 performs is demonstrated.
The process shown in FIG. 3 shows the first control mode executed by the control unit 40.
As shown in FIG. 3, in step S <b> 301, the control unit 40 detects the supply amount A <b> 1 that the coal feeder 20 supplies to the vertical roller mill 10 per unit time (for example, 2 minutes). The control unit 40 detects the supply amount A1 based on the speed at which the transport unit 22 transports the solid fuel.

  In step S <b> 302, the control unit 40 detects an increase amount A <b> 2 per unit time (for example, 2 minutes) of uncrushed solid fuel accumulated in the bottom 11 a of the housing 11. The control unit 40 detects the increase amount A2 from the difference between the first load signal obtained from the load cell 19 at the first timing and the second load signal obtained from the load cell 19 at the second timing. Here, the difference time between the first timing and the second timing is the unit time described above.

  In step S303, the control unit 40 determines whether or not the value of the increase amount A2 / supply amount A1 exceeds a predetermined limit value Lv. The control unit 40 proceeds to step S304 when determining that the value of the increase amount A2 / supply amount A1 exceeds the predetermined limit value Lv, and otherwise ends the process.

  In step S <b> 304, the control unit 40 controls the urging mechanism 15 to increase the urging force of the roller 13 by the urging mechanism 15. As the urging force of the roller 13 increases, the pressing force with which the roller 13 presses the rotary table 12 increases, and the amount of solid fuel pulverized by the roller 13 increases.

Here, an increase limit amount is provided for the increase amount of the urging force of the roller 13 by the urging mechanism 15. This is because if the urging force of the roller 13 by the urging mechanism 15 is increased without limit, the roller 13 and the rotary table 12 will be excessively worn.
Therefore, the increase amount of the urging force that the control unit 40 increases in step S304 is an amount smaller than the increase limit amount.

In step S <b> 305, the control unit 40 detects the supply amount A <b> 1 again at a timing when a predetermined time has elapsed after increasing the urging force of the roller 13 by the urging mechanism 15.
In step S306, the control unit 40 detects the increase amount A2 again at a timing when a predetermined time has elapsed since the urging force of the roller 13 by the urging mechanism 15 is increased.

In step S307, the control unit 40 determines whether or not the value of the increase amount A2 / supply amount A1 exceeds a predetermined limit value Lv. The control unit 40 proceeds to step S308 when determining that the value of increase amount A2 / supply amount A1 exceeds the predetermined limit value Lv, and otherwise ends the process.
Here, the case of terminating the process is a case where the value of the increase amount A2 / the supply amount A1 becomes equal to or less than the predetermined limit value Lv. In this case, the control unit 40 determines that the problem that a large amount of unpulverized solid fuel accumulates in the bottom 11a of the housing 11 has been suppressed, and ends the present process.

In step S308, the control unit 40 determines whether or not the increase amount of the urging force increased in step S304 has reached the increase limit amount. If not, the control unit 40 returns the process to step S304 again. By returning the process to step S304, the control unit 40 repeats the process of increasing the urging force of the roller 13 by the urging mechanism 15 until the value of the increase amount A2 / the supply amount A1 becomes equal to or less than the predetermined limit value Lv.
If the control unit 40 determines in step S308 that the increase amount of the urging force has reached the increase limit amount, the control unit 40 proceeds to step S401 in FIG.

  The process shown in FIG. 4 shows the second control mode executed by the control unit 40. The second control mode is a control mode that is executed when the value of the increase amount A2 / supply amount A1 exceeds the predetermined limit value Lv even when the control unit 40 executes the first control mode.

  In step S401, the control unit 40 controls the rotation speed of the motor 16a of the classification unit 16 so as to decrease the rotation speed of the classification unit 16. As the rotational speed of the classifying unit 16 decreases, the amount of fine fuel supplied from the vertical roller mill 10 to the boiler 200 increases. Thereby, the increase in the accumulation amount of the unpulverized solid fuel accumulated in the bottom portion 11a of the housing 11 is suppressed.

Here, a reduction limit amount is provided for the reduction amount of the rotation speed of the classification unit 16. This is because if the number of rotations of the classifying unit 16 is decreased without limit, the pulverized fuel having an excessively large particle diameter is supplied to the boiler 200.
Therefore, the amount of decrease in the number of rotations that is reduced by the control unit 40 in step S401 is an amount smaller than the reduction limit amount.

In step S <b> 402, the control unit 40 detects the supply amount A <b> 1 again at a timing when a predetermined time has elapsed since the rotation number of the classifying unit 16 is decreased.
In step S403, the control unit 40 detects the increase amount A2 again at a timing when a predetermined time has elapsed since the rotation number of the classifying unit 16 was decreased.

  In step S404, the control unit 40 determines whether or not the value of the increase amount A2 / supply amount A1 exceeds a predetermined limit value Lv. When it is determined that the value of increase amount A2 / supply amount A1 exceeds the predetermined limit value Lv, the control unit 40 proceeds to step S405, and otherwise ends the process.

  In step S405, the control unit 40 determines whether or not the reduction amount of the rotational speed reduced in step S401 has reached the reduction limit amount. If not, the control unit 40 returns the process to step S401 again. By returning the process to step S401, the control unit 40 repeats the process of decreasing the rotational speed of the classification unit 16 until the value of the increase amount A2 / supply amount A1 becomes equal to or less than the predetermined limit value Lv. If the control unit 40 determines in step S405 that the amount of decrease in the rotational speed has reached the increase limit amount, the control unit 40 proceeds to step S501 in FIG.

  The process shown in FIG. 5 shows the third control mode executed by the control unit 40. The third control mode is a control mode that is executed when the value of the increase amount A2 / supply amount A1 exceeds the predetermined limit value Lv even when the control unit 40 executes the second control mode.

  In step S501, the control unit 40 controls the blowing amount of the hot gas blower 30a and the cold gas blower 30b of the blowing unit 30 so as to increase the blowing amount of the blowing unit 30. The excess rate of primary air increases with an increase in the amount of air blown by the blower 30. The supply amount of the pulverized fuel supplied from the vertical roller mill 10 to the boiler 200 increases with the increase in the blown amount. Thereby, the increase in the accumulation amount of the unpulverized solid fuel accumulated in the bottom portion 11a of the housing 11 is suppressed.

Here, an increase limit amount is provided for the increase amount of the air blowing amount of the air blowing unit 30. This is because, if the amount of air blown by the air blower 30 is increased without limit, the driving power of the air blower 30 is excessively increased and the excess ratio of primary air is excessively increased.
Therefore, the increase amount of the air flow rate that is increased by the control unit 40 in step S501 is smaller than the increase limit amount.

In step S <b> 502, the control unit 40 detects the supply amount A <b> 1 again at a timing when a certain time has elapsed after increasing the air blowing amount of the air blowing unit 30.
Further, in step S503, the control unit 40 detects the increase amount A2 again at a timing when a predetermined time has elapsed after the increase in the air blowing amount of the air blowing unit 30.

  In step S504, the control unit 40 determines whether or not the value of the increase amount A2 / supply amount A1 exceeds a predetermined limit value Lv. When it is determined that the value of increase amount A2 / supply amount A1 exceeds predetermined limit value Lv, control unit 40 proceeds to step S505, and otherwise ends the process.

  In step S505, the control unit 40 determines whether or not the increase amount of the air flow increased in step S501 has reached the increase limit amount. If not, the control unit 40 returns the process to step S501 again. By returning the process to step S501, the control unit 40 repeats the process of increasing the air flow rate of the air blowing unit 30 until the value of the increase amount A2 / the supply amount A1 becomes equal to or less than the predetermined limit value Lv. When the control unit 40 determines in step S505 that the increase amount of the blown air amount has reached the increase limit amount, the control unit 40 advances the processing to step S601 in FIG.

  The process shown in FIG. 6 shows a fourth control mode executed by the control unit 40. The fourth control mode is a control mode that is executed when the value of the increase amount A2 / the supply amount A1 exceeds the predetermined limit value Lv even when the control unit 40 executes the third control mode.

  In step S <b> 601, the control unit 40 controls the transport speed at which the transport unit 22 of the coal feeder 20 transports the solid fuel so as to reduce the solid fuel supply amount A <b> 1 by the coal feeder 20. As the supply amount A1 by the coal feeder 20 decreases, the supply amount of fine fuel supplied from the vertical roller mill 10 to the boiler 200 decreases. Since the supply amount A1 by the coal feeder 20 decreases, an increase in the accumulation amount of uncrushed solid fuel accumulated in the bottom portion 11a of the housing 11 is suppressed.

Here, the amount of decrease in the solid fuel supply amount A1 by the coal feeder 20 is provided with a reduction limit amount. This is because if the supply amount A1 of the solid fuel by the coal feeder 20 is reduced without limitation, the supply amount of the fine fuel supplied from the vertical roller mill 10 to the boiler 200 is excessively reduced.
Therefore, the increase amount of the solid fuel supply amount A1 that is reduced by the control unit 40 in step S601 is smaller than the increase limit amount.

In step S <b> 602, the control unit 40 detects the supply amount A <b> 1 again at a timing when a certain time has elapsed since the supply amount A <b> 1 of the solid fuel by the coal feeder 20 is decreased.
Further, in step S603, the control unit 40 detects the increase amount A2 again at a timing when a predetermined time has elapsed since the supply amount A1 of the solid fuel by the coal feeder 20 is decreased.

  In step S604, the control unit 40 determines whether or not the value of the increase amount A2 / supply amount A1 exceeds a predetermined limit value Lv. When it is determined that the value of increase amount A2 / supply amount A1 exceeds the predetermined limit value Lv, the control unit 40 advances the process to step S605, and otherwise ends the process.

  In step S605, the control unit 40 determines whether or not the reduction amount of the solid fuel supply amount A1 reduced in step S601 has reached the reduction limit amount, and if not, returns the processing to step S601 again. . By returning the process to step S601, the control unit 40 repeats the process of decreasing the solid fuel supply amount A1 by the coal feeder 20 until the increase amount A2 / supply amount A1 becomes equal to or less than the predetermined limit value Lv. . If the control unit 40 determines in step S605 that the reduction amount of the supply amount A1 has reached the reduction limit amount, the control unit 40 ends this process.

Next, the relationship between the solid fuel supply amount A1 and the solid fuel supply amount A1 with respect to the solid fuel supply amount A1 will be described in comparison with this embodiment and the comparative example with reference to FIG. .
The solid line shown in FIG. 7 shows the relationship between the solid fuel supply amount A1 and the increase amount A2 of the unpulverized solid fuel with respect to the solid fuel supply amount A1 in the present embodiment. On the other hand, the broken line shown in FIG. 7 shows the relationship between the solid fuel supply amount A1 and the increase amount A2 of the unpulverized solid fuel with respect to the solid fuel supply amount A1 in the comparative example. The comparative example is an example in which none of the first control mode, the second control mode, the third control mode, and the fourth control mode shown in FIGS. 3 to 6 is executed.

As shown in FIG. 7, in any of the present embodiment and the comparative example, the increase amount increases with the increase in the solid fuel supply amount A1 until the increase amount A2 / supply amount A1 reaches the predetermined limit value Lv. The value of amount A2 / supply amount A1 increases.
In this embodiment, when the increase amount A2 / supply amount A1 reaches the predetermined limit value Lv, the increase amount A2 / supply amount A1 does not increase even if the solid fuel supply amount A1 increases. The limit value Lv is maintained. This is because an increase in the value of the increase amount A2 / supply amount A1 is suppressed by executing the first control mode, the second control mode, the third control mode, and the fourth control mode.

  On the other hand, in the comparative example, even if the value of the increase amount A2 / supply amount A1 reaches the predetermined limit value Lv, the value of the increase amount A2 / supply amount A1 increases as the solid fuel supply amount A1 increases. . This is because the first control mode, the second control mode, the third control mode, and the fourth control mode are not executed, and an increase in the increase amount A2 / supply amount A1 is not suppressed.

In the above description, the control unit 40 executes each control mode with increasing priority in the order of the first control mode, the second control mode, the third control mode, and the fourth control mode. Other embodiments may be possible.
For example, the control unit 40 may execute these control modes with higher priority in the second control mode than in the first control mode. As described above, when the increase amount A2 with respect to the supply amount A1 exceeds the predetermined limit value Lv, the control unit 40 decreases the first control mode in which the urging force by the urging mechanism 15 is increased and the rotation speed of the classification unit 16. At least one of the second control modes may be executed.

The operations and effects of the solid fuel crusher 100 of the present embodiment described above will be described.
According to the solid fuel pulverization apparatus 100 of the present embodiment, the load cell 19 detects the accumulation amount of the unpulverized solid fuel accumulated in the bottom portion 11a of the housing 11 and accumulates the solid fuel supply amount A1 by the coal feeder 20. When the increase amount A2 exceeds the predetermined limit value Lv, at least one of the first control mode for increasing the urging force by the urging mechanism 15 and the second control mode for decreasing the rotation speed of the classifying unit 16 is executed. Is done. Therefore, when the first control mode is executed, the solid fuel is pulverized by the roller 13 and the rotary table 12 as the urging force by the urging mechanism 15 increases. As the pulverization of the solid fuel is promoted, the pulverized fuel supplied from the classification unit 16 to the outside increases, and the increase in the accumulated amount of the unpulverized solid fuel accumulated in the bottom portion 11a of the housing 11 is suppressed. .

In addition, when the second control mode is executed, the finely pulverized fuel supplied to the outside from the classifying unit 16 increases as the rotation speed of the classifying unit 16 decreases, and the unpulverized fuel accumulated in the bottom 11a of the housing 11 is increased. An increase in the amount of accumulated solid fuel is suppressed.
As described above, according to the solid fuel pulverization apparatus 100 of the present embodiment, a large amount of unpulverized solid fuel accumulates in the bottom portion 11a of the housing 11 that accommodates the rotary table 12, the roller 13, and the classification unit 16 therein. Can be suppressed.

In the solid fuel crusher 100 of the present embodiment, the control unit 40 executes the first control mode when the increase amount A2 with respect to the supply amount A1 exceeds the predetermined limit value Lv, and executes the first control mode. When the increase amount A2 with respect to the supply amount A1 exceeds the predetermined limit value Lv, the second control mode is executed.
By doing in this way, since the 1st control mode which does not reduce the classification performance of pulverized fuel is performed preferentially over the 2nd control mode, it does not reduce the classification performance of pulverized fuel, but it is in the bottom 11a of housing 11 A problem that a large amount of unground solid fuel accumulates can be suppressed.

Further, even if the first control mode is executed, if the increase amount A2 with respect to the supply amount A1 exceeds the predetermined limit value Lv, the second control mode is executed, so that uncrushed solid fuel is present at the bottom 11a of the housing 11. Problems that accumulate in large quantities can be reliably suppressed.
Here, the first control mode is prioritized over the second control mode because the solid fuel pulverization apparatus 100 is more effective when the pulverized fuel classification performance is lowered than when the urging force is increased by the urging mechanism 15. This is because the adverse effect on the driving performance is large.

Further, in the solid fuel pulverization apparatus 100 of the present embodiment, the control unit 40, even when the second control mode is executed, when the increase amount A2 with respect to the supply amount A1 exceeds the predetermined limit value Lv, A third control mode for increasing the air flow rate is executed.
By doing so, the second control mode that does not increase the excess rate of primary air is executed with priority over the third control mode, and therefore, the bottom portion 11a of the housing 11 does not increase the excess rate of primary air. A problem that a large amount of unground solid fuel accumulates can be suppressed.

Further, even if the second control mode is executed, the third control mode is executed when the increase amount A2 with respect to the supply amount A1 exceeds the predetermined limit value Lv. Therefore, the unpulverized solid fuel is present at the bottom 11a of the housing 11. Problems that accumulate in large quantities can be reliably suppressed.
Here, the second control mode is prioritized over the third control mode because the operation of the solid fuel crusher 100 is performed more when the excess ratio of the primary air is increased than when the classification performance of the pulverized fuel is decreased. This is because the adverse effect on performance is large.

Further, in the solid fuel crusher 100 of the present embodiment, the control unit 40, even when the third control mode is executed, when the increase amount A2 with respect to the supply amount A1 exceeds the predetermined limit value Lv, the solid fuel by the coal feeder 20 The fourth control mode for decreasing the supply amount A1 of the first is executed.
By doing in this way, the 3rd control mode which does not reduce supply amount A1 of solid fuel by coal feeder 20 is performed preferentially over the 4th control mode. Therefore, it is possible to suppress a problem that a large amount of unground solid fuel accumulates in the bottom 11a of the housing 11 without reducing the solid fuel supply amount A1 by the coal feeder 20.

Even if the third control mode is executed, if the increase amount A2 with respect to the supply amount A1 exceeds the predetermined limit value Lv, the fourth control mode is executed, so that uncrushed solid fuel is present at the bottom 11a of the housing 11. Problems that accumulate in large quantities can be reliably suppressed.
Here, the third control mode is prioritized over the fourth control mode because the solid fuel supply amount A1 by the coal feeder 20 is reduced more than the primary air excess rate is increased. This is because the adverse effect on the operation performance of the fuel crusher 100 is great.

In the solid fuel pulverization apparatus 100 of the present embodiment, the load cell 19 directly detects the accumulated amount of unground crushed solid fuel that has fallen on the bottom 11 a of the housing 11 as the load of the recovery unit 18.
In this way, the accumulated amount of unground solid fuel that does not fall back to the bottom 11a of the housing 11 and return to the turntable 12 is directly detected, and a large amount of unground solid fuel is detected at the bottom of the housing 11. The trouble accumulated in 11a can be suppressed.

[Second Embodiment]
Next, a solid fuel crusher 100 ′ according to a second embodiment of the present invention will be described with reference to the drawings.
The present embodiment is a modification of the first embodiment, and is the same as the first embodiment unless otherwise described below.

In the solid fuel pulverization apparatus 100 according to the first embodiment, the load cell 19 directly detects the accumulated amount of uncrushed solid fuel that has fallen on the bottom 11a of the housing 11 as a load.
On the other hand, the solid fuel pulverization apparatus 100 ′ of the present embodiment detects the accumulated amount of unground pulverized solid fuel deposited on the rotary table 12.

As shown in FIG. 8, the vertical roller mill 10 ′ included in the solid fuel crusher 100 ′ of the present embodiment includes a measurement unit 17 a attached to the outer peripheral surface on the lower end side of the solid fuel input unit 17.
The measuring unit 17a is a device that measures the height h of unground solid fuel deposited on the central portion of the turntable 12 from the measuring unit 17a. The measuring unit 17a is based on the difference between the distance to the center of the turntable 12 detected in a state where no solid fuel is accumulated and the distance to the upper surface of the uncrushed solid fuel detected in the state where the solid fuel is accumulated. The height h is measured.

  Various measuring units 17a can be used. For example, the height h may be calculated from an image obtained by capturing the center of the rotary table 12 with a camera. Further, for example, the height h may be measured by microwaves or infrared rays. Further, for example, a contact type level meter that determines whether the height h exceeds a predetermined height may be employed.

The control unit 40 of the present embodiment detects the increase amount A3 per unit time of the height h measured by the measurement unit 17a instead of detecting the increase amount A2 of the unpulverized solid fuel in the first embodiment. To do.
Further, the control unit 40 according to the present embodiment changes the determination of increase amount A2 / supply amount A1> predetermined limit value Lv ′ in the first embodiment, and increases amount A3 / supply amount A1> predetermined limit value Lv. Make a judgment.
The processing executed by the control unit 40 of the present embodiment is the same as the processing executed by the control unit 40 of the first embodiment except for the above points.

In the above description, the increase amount A3 per unit time of the height h measured by the measurement unit 17a is used as a determination criterion for the process executed by the control unit 40. However, other modes may be used.
For example, a value obtained by dividing the height h measured by the measurement unit 17a by the diameter of the rotary table 12 may be used as a determination criterion for the process executed by the control unit 40. In this case, the height h with respect to the diameter of the turntable 12 can be used as a criterion for determination, not the absolute height of the unpulverized solid fuel deposited on the turntable 12.

According to the solid fuel pulverization apparatus 100 ′ of the present embodiment, such a problem may occur before the problem that the unpulverized solid fuel falls to the bottom 11 a of the housing 11 and accumulates in large quantities occurs. It can be detected in advance.
This embodiment is particularly effective when using a solid fuel that is difficult to grind and easily deposits on the turntable 12, such as coal or biomass fuel with a low Hardgrove Grindability Index.

10, 10 'Vertical roller mill 11 Housing 11a Bottom portion 11b Recovery hole 12 Rotary table 12a Recovery rod 13 Roller 14 Drive unit 15 Energizing mechanism 16 Classification unit 16a Motor 16b Outlet 17 Solid fuel input unit 17a Measurement unit 18 Recovery unit 18a Recovery duct 19 Load cell (load detector)
20 Coal feeder (fuel supply unit)
23 Motor 30 Air blower 40 Control part 50 Flow path 60 Supply flow path 100, 100 'Solid fuel crusher 200 Boiler

Claims (7)

A rotary table that is rotated by a driving force from a driving unit;
A fuel supply unit for supplying solid fuel to the rotary table;
A roller for pulverizing the solid fuel on the rotary table;
An urging mechanism for generating an urging force for pressing the roller against the rotary table;
A rotary classifying unit that is provided above the rotary table and classifies the solid fuel pulverized by the roller into a finely divided fuel smaller than a predetermined particle size;
An air blowing section for blowing an oxidizing gas for guiding the solid fuel crushed by the roller to the classification section;
A housing that houses the rotary table, the roller, and the classifying unit;
A detection unit for detecting an accumulation amount of the unpulverized solid fuel accumulated below the housing;
A controller that controls the urging force of the urging mechanism and the number of rotations of the classifying unit,
The control unit includes a first control mode for increasing the urging force by the urging mechanism and the classification when an increase amount of the accumulation amount with respect to the solid fuel supply amount by the fuel supply unit exceeds a predetermined limit value. A solid fuel pulverization apparatus that executes at least one of the second control modes for reducing the rotational speed of the unit.   The control unit executes the previous first control mode when the increase amount with respect to the supply amount exceeds the predetermined limit value, and the increase amount with respect to the supply amount is the predetermined amount even when the first control mode is executed. The solid fuel pulverization apparatus according to claim 1, wherein the second control mode is executed when a limit value is exceeded.   In the third control mode, the control unit increases the blowing amount of the oxidizing gas by the blowing unit when the increase amount with respect to the supply amount exceeds the predetermined limit value even when the second control mode is executed. The solid fuel pulverization apparatus according to claim 2 to be executed.   The said control part performs the 4th control mode which decreases the said supply amount by the said fuel supply part, when the said increase amount with respect to the said supply amount exceeds the said predetermined limit value, even if it performs the said 3rd control mode. Item 4. The solid fuel pulverizing apparatus according to Item 3.   5. The solid fuel supply device according to claim 1, wherein the detection unit detects an accumulation amount of the unpulverized solid fuel that has fallen to a bottom portion of the housing. 6.   5. The solid fuel supply apparatus according to claim 1, wherein the detection unit detects an accumulation amount of the unpulverized solid fuel accumulated on the rotary table. 6. A rotating table that rotates by a driving force from a driving unit; a fuel supply unit that supplies solid fuel to the rotating table; a roller that crushes the solid fuel on the rotating table; and a roller that presses the roller against the rotating table. An urging mechanism for generating a force, a rotary classification unit provided above the rotary table and pulverized by the roller to classify the solid fuel into fine pulverized fuel smaller than a predetermined particle size, and the pulverized by the roller A control method for a solid fuel supply apparatus, comprising: a blower that blows an oxidizing gas for guiding solid fuel to the classification unit; and a housing that houses the rotary table, the roller, and the classification unit. And
A detection step of detecting an accumulation amount of the unpulverized solid fuel accumulated below the housing;
A first control step of increasing the urging force by the urging mechanism when an increase amount of the accumulated amount with respect to the solid fuel supply amount by the fuel supply unit exceeds a predetermined limit value;
A control method for a solid fuel supply device, comprising: a second control step of reducing the rotational speed of the classifying unit when the increase amount with respect to the supply amount exceeds the predetermined limit value.

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