CN109622148B - Solid fuel pulverizer and method for controlling solid fuel pulverizer - Google Patents
Solid fuel pulverizer and method for controlling solid fuel pulverizer Download PDFInfo
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- CN109622148B CN109622148B CN201811170916.6A CN201811170916A CN109622148B CN 109622148 B CN109622148 B CN 109622148B CN 201811170916 A CN201811170916 A CN 201811170916A CN 109622148 B CN109622148 B CN 109622148B
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- 239000004449 solid propellant Substances 0.000 title claims abstract description 128
- 238000000034 method Methods 0.000 title claims abstract description 22
- 238000000227 grinding Methods 0.000 claims abstract description 53
- 230000007423 decrease Effects 0.000 claims abstract description 37
- 238000010298 pulverizing process Methods 0.000 claims description 49
- 239000000446 fuel Substances 0.000 claims description 37
- 238000004364 calculation method Methods 0.000 claims description 36
- 230000009467 reduction Effects 0.000 claims description 23
- 239000000843 powder Substances 0.000 claims description 22
- 239000002245 particle Substances 0.000 claims description 16
- 230000003247 decreasing effect Effects 0.000 abstract description 19
- 230000004043 responsiveness Effects 0.000 abstract description 11
- 239000003245 coal Substances 0.000 description 52
- 230000008859 change Effects 0.000 description 31
- 238000010586 diagram Methods 0.000 description 13
- 238000001514 detection method Methods 0.000 description 12
- 238000007664 blowing Methods 0.000 description 7
- 239000000567 combustion gas Substances 0.000 description 5
- 230000002123 temporal effect Effects 0.000 description 5
- 238000012886 linear function Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 239000012159 carrier gas Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
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- 230000000087 stabilizing effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C15/00—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs
- B02C15/007—Mills with rollers pressed against a rotary horizontal disc
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
- B02C23/02—Feeding devices
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
- B02C23/18—Adding fluid, other than for crushing or disintegrating by fluid energy
- B02C23/20—Adding fluid, other than for crushing or disintegrating by fluid energy after crushing or disintegrating
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C25/00—Control arrangements specially adapted for crushing or disintegrating
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K3/00—Feeding or distributing of lump or pulverulent fuel to combustion apparatus
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C15/00—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs
- B02C2015/002—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs combined with a classifier
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- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Crushing And Grinding (AREA)
- Disintegrating Or Milling (AREA)
Abstract
The invention provides a solid fuel pulverizer and a control method thereof, which can improve the responsiveness of the increase or decrease of the load of a boiler and the following performance of the load of the boiler relative to a target value load when the load of the boiler is increased or decreased. The disclosed device is provided with: a first calculating unit for calculating a reference revolution command value (Rst) of the grinding table according to the load of the boiler; a second calculating unit for calculating the added rotation number command value of the grinding table corresponding to the load; and a control unit for controlling the rotation number of the grinding table driven by the driving unit based on a target rotation number command value (Rta) obtained by adding the reference rotation number command value (Rst) and the added rotation number command value, wherein when a load command for increasing the load of the boiler from a first load (L1) to a second load (L2) is input, the second calculating unit gradually reduces the added rotation number command value from an initial value (Rad0) to zero according to the increase of the load.
Description
Technical Field
The present invention relates to a solid fuel pulverizer and a method for controlling the solid fuel pulverizer.
Background
For example, a coal-fired thermal power generation unit generates steam by heat exchange with combustion gas generated by burning pulverized coal pulverized by a coal pulverizer in a boiler furnace, and generates power by driving a turbine with the steam.
Here, the load (power generation output) during operation of the coal-fired thermal power plant is not limited to a fixed load, and may be operated in accordance with a load change. For example, when a coal-fired thermal power plant is associated with an electric power system, the load of the coal-fired thermal power plant may be rapidly changed in accordance with a request from the system side for the purpose of stabilizing the system frequency or the like.
However, in the coal-fired thermal power plant, even if the supply amount of coal to the coal pulverizer is changed, a time lag (coal discharge delay) occurs until the coal discharge amount of coal discharged from the coal pulverizer is changed. Therefore, it is difficult to rapidly change the load of the coal-fired thermal power plant.
In this regard, patent document 1 discloses the following technique: in order to eliminate the coal discharge delay, the rotational speed of the table (crushing table) is determined based on a parameter relating to a change in the load of the generator and the coal supply amount command value. Patent document 2 discloses a method for controlling a vertical mill in which the amount of coal supplied is increased or decreased in accordance with an increase or decrease in the load of the vertical mill, and the rotational speed of a table is increased or decreased so as to compensate for an excess or deficiency in the amount of coal output due to a time delay from the coal supply to the coal output.
Prior art documents
Patent document
Patent document 1: japanese laid-open patent publication No. 2015-100740
Patent document 2: japanese laid-open patent publication No. 63-62556
Disclosure of Invention
Problems to be solved by the invention
In patent document 1, a base rotational speed of a table is determined based on a coal supply amount, a preceding rotational speed is determined based on a change rate of a load required by a generator, and the like, and the rotational speed of the table is determined by adding the base rotational speed and the preceding rotational speed.
However, in patent document 1, as shown in fig. 6, before the generator load reaches the target load, the preceding rotational speed is sequentially calculated and added to the base rotational speed. Therefore, the temporal change in the rotation speed of the table becomes excessively large, and the drive power of the drive unit for rotating the table temporarily increases, which may cause the amount of pulverized coal to be unstable. Further, when the type of coal is different, it is necessary to set the coefficient of the function for controlling the table rotation speed again by an experiment or the like, and when there are a plurality of functions and coefficients, it is easy to make the operation complicated.
In patent document 2, as shown in fig. 5, the set value for increasing the rotational speed of the table is gradually increased from zero simultaneously with the load command for increasing the boiler load, and after the boiler load reaches the target load, the set 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 rotation speed of the table with respect to the load command may be insufficient. Further, since the set value is gradually decreased after the boiler load reaches the target load, the boiler load may exceed the target load and excessively increase.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a solid fuel pulverizer and a control method thereof, which can improve responsiveness of a rotation speed of a pulverizing table to increase or decrease of a load of a boiler and follow-up of the load of the boiler to a target value load, when the load of the boiler is increased or decreased.
Means for solving the problems
In order to solve the above problem, the present application adopts the following aspects.
A solid fuel pulverizer according to an aspect of the present application is a solid fuel pulverizer for pulverizing a solid fuel and supplying the pulverized solid fuel to a boiler, and includes: a crushing workbench; a driving unit that generates a driving force for rotating the mill table; a roller that pulverizes the solid fuel supplied from a fuel supply section to the pulverization table between the roller and the pulverization table; a classifying section that classifies the solid fuel pulverized by the roller into a fine powder fuel having a particle size smaller than a predetermined particle size and carries the fine powder fuel out of the solid fuel pulverizing apparatus; a first calculation unit that calculates a reference rotation number command value of the grinding table according to a load of the boiler; a second calculating unit that calculates an added rotation number command value of the grinding table according to the load; and a control unit that controls the rotation number of the grinding table driven by the drive unit based on a target rotation number command value obtained by adding the reference rotation number command value to the added rotation number command value, wherein the second calculation unit gradually decreases the added rotation number command value from an initial value to zero in accordance with an increase in the load when a load command for increasing the load of the boiler from a first load to a second load is input.
According to the solid fuel pulverizer of one aspect of the present application, when a load command for increasing the load of the boiler is input, an initial value greater than zero is given as the added rotation number command value, and therefore, the responsiveness of the increase in the rotation speed of the pulverizing table (or also referred to as a rotary table) to the load command can be improved. Further, since the added rotation number command value is gradually reduced from the initial value to zero in accordance with the increase in the load, the rotation speed of the grinding table can be set to a speed corresponding to the reference rotation number command value at the time point when the load of the boiler becomes the second load. Therefore, the load of the boiler does not excessively increase beyond the target load, and the simple added rotation number command value can be used to improve the following performance with respect to the target load.
In the solid fuel pulverizer according to the aspect of the present application, when a load command for increasing the load of the boiler from the first load to a third load larger than the second load is input, the second calculator may gradually decrease the added rotation number command value from the initial value to zero in accordance with an increase from the first load to the second load, and gradually decrease the added rotation number command value from the initial value to zero in accordance with an increase from the second load to the third load.
When the load of the boiler is increased from the first load to the third load larger than the second load, the added rotation number command value becomes zero at the second load, and therefore, the rotation number of the grinding table can be prevented from being excessively increased as compared with a case where the added rotation number command value is maintained at a value larger than zero until the first load reaches the third load. Therefore, the excessive increase of the coal output amount accompanying the increase of the number of revolutions of the grinding table can be suppressed.
In the solid fuel pulverizer according to one aspect of the present application, the second calculation unit may set the initial value in accordance with an increase in the load per unit time.
By setting the initial value in accordance with the amount of increase in the load per unit time, an appropriate initial value in accordance with the amount of increase in the load per unit time can be set, and the ability of the number of revolutions of the mill table to follow changes in the load can be improved, and an excessive increase in the coal output can be suppressed.
In the solid fuel pulverizer according to one aspect of the present application, the second calculating unit may set the added rotation number command value to zero when the load is lower than a predetermined load.
In this way, when a load lower than a predetermined load is not likely to cause a coal discharge delay, the number of revolutions of the grinding table can be set to a value corresponding to the reference revolution command value.
In the solid fuel pulverizer according to one aspect of the present application, the second calculating unit may calculate a command value of the subtracted rotational speed of the pulverizing table according to the load, and when a load command for reducing the load of the boiler from the second load to the first load is input, the second calculating unit may gradually reduce the command value of the subtracted rotational speed from an initial value to zero according to the reduction of the load.
According to the solid fuel pulverizer of one aspect of the present application, when a load command for reducing the load of the boiler is input, an initial value greater than zero is given as the subtraction rotation number command value, and therefore, the responsiveness of the reduction in the rotation speed of the pulverizing table to the load command can be improved. Further, since the subtraction rotation number command value is gradually reduced from the initial value to zero in accordance with the reduction of the load, the rotation speed of the grinding table can be set to a speed corresponding to the reference rotation number command value at the time point when the load of the boiler becomes the first load. Therefore, the load of the boiler does not excessively decrease beyond the target load, and the following ability to the target load can be improved by using a simple subtraction rotation number command value.
In the solid fuel pulverizer according to the aspect of the present application, 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 second calculation unit may gradually reduce the subtraction rotation number command value from the initial value to zero in accordance with a reduction from the third load to the second load, and gradually reduce the subtraction rotation number command value from the initial value to zero in accordance with a reduction from the second load to the first load.
When the load of the boiler is reduced from the third load larger than the second load to the first load, the command value of the subtraction rotation number becomes zero at the second load, and therefore, the rotation number of the grinding table can be prevented from being excessively reduced as compared with the case where the command value of the subtraction rotation number is maintained at a value larger than zero until the third load reaches the first load. Therefore, the excessive decrease in the amount of coal output due to the decrease in the number of revolutions of the grinding table can be suppressed.
In the solid fuel pulverizer according to one aspect of the present application, the second calculation unit may set the initial value in accordance with a decrease amount of the load per unit time.
By setting the initial value in accordance with the amount of reduction of the load per unit time, an appropriate initial value in accordance with the amount of reduction of the load per unit time can be set, and the ability of the number of revolutions of the grinding table to follow changes in the load can be improved, and the amount of coal produced can be suppressed from excessively decreasing.
A method for controlling a solid fuel pulverizer that pulverizes a solid fuel and supplies the pulverized solid fuel to a boiler according to an aspect of the present application is a method for controlling a solid fuel pulverizer that includes: a crushing workbench; a driving unit that generates a driving force for rotating the mill table; a roller that pulverizes the solid fuel supplied from a fuel supply portion to the pulverization table between the roller and the pulverization table; and a classifying unit that classifies the solid fuel pulverized by the roller into a fine powder fuel having a particle size smaller than a predetermined particle size and carries out the fine powder fuel from the solid fuel pulverizing apparatus, the control method including: a first calculation step of calculating a reference revolution command value of the grinding table according to a load of the boiler; a second calculating step of calculating an added rotation number command value of the grinding table corresponding to the load; and a control step of controlling the rotation number of the grinding table driven by the drive unit based on a target rotation number command value obtained by adding the reference rotation number command value to the added rotation number command value, wherein in the second calculation step, the added rotation number command value is gradually decreased from an initial value to zero in accordance with an increase in the load when a load command for increasing the load of the boiler from a first load to a second load is input.
According to the control method of the solid fuel pulverizer of one aspect of the present application, when a load command for increasing the load of the boiler is input, an initial value greater than zero is given as the added rotation number command value, and therefore, the responsiveness of the increase in the rotation speed of the pulverizing table to the load command can be improved. Further, since the added rotation number command value is gradually reduced from the initial value to zero in accordance with the increase in the load, the rotation speed of the grinding table can be set to a speed corresponding to the reference rotation number command value at the time point when the load of the boiler becomes the second load. Therefore, the load of the boiler does not excessively increase beyond the target load, and the simple added rotation number command value can be used to improve the following performance with respect to the target load.
In the method for controlling a solid fuel pulverizer according to one aspect of the present application, a third calculation step may be provided in which a subtraction rotation number command value of the pulverizer table corresponding to the load is calculated, and when a load command for reducing the load of the boiler from a second load to a first load is input, the subtraction rotation number command value may be gradually reduced from the initial value to zero according to the reduction in the load in the third calculation step.
According to the control method of the solid fuel pulverizer of one aspect of the present application, when a load command for reducing the load of the boiler is input, an initial value greater than zero is given as the subtraction rotation number command value, and therefore, the responsiveness of the reduction in the rotation speed of the pulverizing table to the load command can be improved. Further, since the subtraction rotation number command value is gradually reduced from the initial value to zero in accordance with the reduction of the load, the rotation speed of the grinding table can be set to a speed corresponding to the reference rotation number command value at the time point when the load of the boiler becomes the first load. Therefore, the load of the boiler does not excessively decrease beyond the target load, and the following ability to the target load can be improved by using a simple subtraction rotation number command value.
Effects of the invention
According to the present application, there can be provided a solid fuel pulverizer and a control method thereof, the solid fuel pulverizer including: when the load of the boiler is increased or decreased, the responsiveness of the rotation speed of the grinding table to the increase or decrease of the load of the boiler and the tracking ability of the load of the boiler to the target value load can be improved.
Drawings
Fig. 1 is a configuration diagram showing a solid fuel pulverizer and a boiler according to a first embodiment of the present application.
Fig. 2 is a configuration diagram showing a schematic configuration of the control device shown in fig. 1.
Fig. 3 is a diagram showing a relationship between a boiler load and a rotation number command value when the boiler load is increased from the first load to the second load in the solid fuel pulverizer of the first embodiment.
Fig. 4 is a diagram showing a relationship between a boiler load and a rotation number command value when the boiler load is decreased from the second load to the first load in the solid fuel pulverizer of the first embodiment.
Fig. 5 is a graph showing a temporal change in the coal output from the solid fuel pulverizer to the boiler when the boiler load is increased in the solid fuel pulverizer of the first embodiment.
Fig. 6 is a diagram showing a relationship between a boiler load and a rotation number command value when the boiler load is increased from a first load to a second load in the solid fuel pulverizer of the second embodiment.
Fig. 7 is a diagram showing a relationship between a boiler load and a rotation number command value when the boiler load is increased from the first load to the third load in the solid fuel pulverizer of the third embodiment.
Fig. 8 is a diagram showing a relationship between a boiler load and a rotation number command value when the boiler load is decreased from the third load to the first load in the solid fuel pulverizer of the third embodiment.
Fig. 9 is a diagram showing a relationship between a boiler load change rate and initial values of an added rotation number command value and an subtracted rotation number command value in the solid fuel pulverizer of the fourth embodiment.
Description of reference numerals:
10 grinding machine
11 casing
12 crushing workbench
13 roller
14 drive part
15 drive shaft
16 classification section
17 fuel supply part
18 motor
19 outlet port
20 coal feeder
30 blower part
30a hot air blower
30b cold air blower
30c hot gas baffle
30d cold air baffle
40 temperature detecting part
50 control device
51 control part
52 detection part
53 first calculating part
54 second calculating unit
100 solid fuel crushing device
100a primary air flow path
100b supply flow path
200 boiler
210 hearth
220 combustor part
L1, L2 boiler load
R revolution command value
Rad-added revolution command value
Rad0 initial value
Rst reference revolution number instruction value
Rsu subtracting the command value of the number of revolutions
Rsu0 initial value
Rta target revolution number command value.
Detailed Description
Next, an embodiment of the solid fuel pulverizer and the control method thereof according to the present invention will be described with reference to the drawings.
[ first embodiment ]
A first embodiment of the present application will be described below with reference to the drawings.
The solid fuel pulverizer 100 of the present embodiment pulverizes a carbon-containing solid fuel such as coal to generate a fine powder fuel, and supplies the fine powder fuel to a burner unit (combustion device) 220 of a boiler 200.
The boiler system including the solid fuel pulverizer 100 and the boiler 200 shown in fig. 1 includes one solid fuel pulverizer 100, but may include a plurality of solid fuel pulverizers 100 corresponding to the plurality of burner units 220 of one boiler 200.
The solid fuel pulverizer 100 of the present embodiment includes a mill 10, a coal feeder 20, an air blowing unit 30, a temperature detection unit 40, and a control device 50.
In the present embodiment, the upward direction represents the direction of the vertically upper side, and the "up" of the upper portion, the upper surface, or the like represents the portion of the vertically upper side. Similarly, "lower" indicates a vertically lower portion.
The mill 10 includes a casing 11, a grinding table 12, a roller 13, a driving unit 14, a driving shaft 15, a classifying unit 16, a fuel supply unit 17, and a motor 18 for driving the classifying unit 16 to rotate.
The casing 11 is a frame formed in a substantially cylindrical shape extending in the vertical direction and houses the pulverization table 12, the rollers 13, the classification section 16, and the fuel supply section 17.
The grinding table 12 is a member having a circular shape in plan view that is rotated by a driving force transmitted from the driving portion 14 via the driving shaft 15, and the grinding table 12 is also called a rotary table, in which solid fuel (coal, for example, in the present embodiment) is supplied from the fuel supply portion 17, and the solid fuel powder is ground between the grinding table and the roller 13. At a plurality of locations on the outer peripheral side of the grinding table 12, blow-out ports (not shown) are provided that discharge primary air, which is a carrier gas and which has flowed in from the primary air flow path 100a, into a space above the grinding table 12 in the casing 11.
A paddle (not shown) is provided above the air outlet to apply a swirling force to the primary air blown out from the air outlet. The primary air given a swirling force by the paddle becomes an air flow having a swirling velocity component, and blows up the solid fuel pulverized on the pulverization table 12 and guides the solid fuel to the upper classification section 16 in the casing 11. The portion of the pulverized solid fuel mixed with the primary air, which is larger than the predetermined particle diameter, is classified by the classifying portion 16, or falls without reaching the classifying portion 16, and returns to the upper surface of the pulverizing table 12.
The roller 13 is a rotating body that pulverizes the solid fuel supplied from the fuel supply unit 17 to the upper surface of the pulverization table 12 between the roller and the pulverization table 12. The roller 13 presses the upper surface of the pulverization table 12 to pulverize the solid fuel in cooperation with the pulverization table 12. In fig. 1, only one roller 13 is shown, but a plurality of rollers 13 are arranged at fixed intervals along the circumferential direction so as to press the upper surface of the grinding table 12. For example, three rollers 13 are arranged on the outer circumferential portion at an angular interval of 120 °. In this case, the distances from the center of the mill table 12 to the portions (pressed portions) where the three rollers 13 contact the upper surface of the mill table 12 are substantially equidistant.
The driving unit 14 is a device that transmits a driving force to the grinding table 12 via a driving shaft 15 to rotate the grinding table 12 about the central axis. The driving unit 14 generates a driving force for rotating the mill table 12.
The classifying unit 16 is a device that classifies the solid fuel pulverized by the roller 13 into a portion larger than a predetermined particle size (for example, 70 to 100 μm) (hereinafter, the pulverized solid fuel having a particle size larger than the predetermined particle size is referred to as "coarse powder fuel") and a portion having a particle size smaller than the predetermined particle size (hereinafter, the pulverized solid fuel having a particle size smaller than the predetermined particle size is referred to as "fine powder fuel"). The classifying portion 16 has, for example, a truncated cone shape in outer shape, is attached to an upper portion in the casing 11 along a cylindrical axis of the casing 11 having a substantially cylindrical shape, and includes a plurality of classifying blades on an outer peripheral side. The classifying portion 16 is rotated about the cylindrical axis of the housing 11 by a driving force applied thereto from a motor 18.
The pulverized solid fuel mixed with the primary air and having reached the classifying portion 16 guides the coarse powder fuel to the pulverizing table 12 and the fine powder fuel (for example, pulverized coal fuel in the present embodiment) to the outlet 19 from the casing 11 and carries out the fine powder fuel in a relative balance between a centrifugal force generated by the rotation of the classifying blades and a centripetal force generated by the flow of the primary air. The fine powder fuel classified by the classifying portion 16 is discharged from the outlet 19 to the supply flow path 100b while being mixed with the primary air. The fine powder fuel mixed with the primary air flowing out of the supply flow path 100b is supplied to the burner unit 220 of the boiler 200.
The fuel supply portion 17 is attached to penetrate the upper end of the housing 11, and supplies the solid fuel, which is charged from above, to a substantially central region of the pulverization table 12. The fuel supply portion 17 is supplied with solid fuel from a coal feeder 20.
The coal feeder 20 includes a hopper 21, a conveying unit 22, and a motor 23. The conveying unit 22 conveys the solid fuel discharged from the lower end portion 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 controlling the supply amount of the solid fuel by the control device 50.
The blowing unit 30 is a device for blowing primary air, which is a carrier gas supplied to the classifying unit 16 and is used for drying the solid fuel pulverized by the rollers 13, into the casing 11.
The air blowing unit 30 includes a hot air blower 30a, a cold air blower 30b, a hot air baffle 30c, and a cold air baffle 30d so as to adjust the temperature of the primary air blown to the casing 11 to an appropriate temperature.
The hot-gas blower 30a is a blower that blows heated primary air supplied through a heat exchanger (heater) such as an air preheater that uses the combustion gas of the boiler 200 as a heat source. A hot air damper (first blowing portion) 30c is provided on the downstream side of the hot air blower 30 a. The opening of the hot gas baffle 30c is controlled by the control device 50. The flow rate of the primary air blown by the hot air blower 30a is determined by the opening degree of the hot air damper 30 c.
The cold air blower 30b is a blower that blows primary air that is outside air at normal temperature. A cold air baffle (second blowing portion) 30d is provided on the downstream side of the cold air blower 30 b. The opening degree of the cold air baffle 30d is controlled by the control device 50. The flow rate of the primary air blown by the cold air blower 30b is determined by the opening degree of the cold air damper 30 d. The flow rate of the primary air is the total flow rate of the primary air blown by the hot air blower 30a and the flow rate of the primary air blown by the cold air blower 30b, and the temperature of the primary air is determined by the mixing ratio of the primary air blown by the hot air blower 30a and the primary air blown by the cold air blower 30b and is controlled by the control device 50.
The temperature detector 40 is a sensor for detecting the temperature of the outlet 19. The temperature detector 40 detects the temperature of the fine powder fuel discharged from the outlet 19 and outputs the detected temperature to the controller 50.
The control device 50 controls each part of the solid fuel pulverizer 100. The control device 50 transmits a drive instruction to the drive unit 14 to control the rotation number of the grinding table 12. The control device 50 can adjust the amount of solid fuel supplied to the fuel supply unit 17 by conveying the solid fuel by the conveying unit 22 by transmitting a drive instruction to the motor 23 of the coal feeder 20. Further, the controller 50 transmits an opening degree instruction to the air blowing unit 30, thereby controlling the opening degrees of the hot air damper 30c and the cold air damper 30d to control the flow rate and the temperature of the primary air.
Next, a boiler 200 that generates steam by burning fine fuel supplied from the solid fuel pulverizer 100 will be described.
The boiler 200 includes a furnace 210 and a burner unit 220.
The burner unit 220 is a device for burning the fine powder fuel using the primary air containing the fine powder fuel supplied from the supply flow path 100b and the secondary air supplied from a heat exchanger (not shown). The combustion of the fine powder fuel proceeds in the furnace 210, and the high-temperature combustion gas passes through a heat exchanger (not shown) such as an evaporator, a superheater, an economizer, and the like, and is then discharged to the outside of the boiler 200.
The combustion gas discharged from the boiler 200 is subjected to a predetermined treatment by an environmental apparatus such as a denitration apparatus, and is sent to a heat exchanger (heater; not shown) such as an air preheater to exchange heat with outside air. The outside air heated by heat exchange with the combustion gas in the heat exchanger is sent to the aforementioned hot air blower 30 a.
The water supplied 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 and high-pressure steam, which is sent to a steam turbine (not shown) to rotate a generator (not shown) to generate electric power.
Next, the control of the rotation number of the crushing table 12 by the control device 50 will be described.
When the load of the boiler 200 is increased, the controller 50 increases the amount of solid fuel supplied from the coal feeder 20 to the fuel supply unit 17. At this time, the controller 50 increases the number of revolutions of the mill table 12 so that the delay (coal discharge delay) of the timing at which the supply amount of the solid fuel supplied from the solid fuel mill 100 to the boiler 200, that is, the amount discharged from the solid fuel mill increases is reduced. The control device 50 transmits the target rotation number command value Rta to the driving unit 14, thereby rotating the grinding table 12 at a rotation number corresponding to the target rotation number command value Rta. Next, a process of calculating target revolution command value Rta by control device 50 will be described.
The control device 50 controls the number of revolutions of the mill table 12 based on the target load of the boiler 200. In this case, the load increase amount per unit time (the load change rate of the boiler) can be set with respect to the time when the load of the boiler 200 reaches the end of the start of the load change. In addition, the present load of the boiler 200 may be detected to improve controllability, and in the present embodiment, a case where the load of the boiler 200 is detected by the detection unit 52 will be described.
Fig. 2 is a configuration diagram showing a schematic configuration of the control device 50. 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 each 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 one or more arithmetic devices.
The control unit 51 calculates a target rotation number command value Rta and transmits the target rotation number command value Rta to the driving unit 14, thereby controlling the rotation number of the grinding table 12 based on the target rotation number command value Rta. The control unit 51 calculates a target rotation command value Rta of the grinding table 12 by adding a reference rotation command value Rst to be described later to the added rotation command value Rad.
The detector 52 may detect the load of the boiler 200 using, for example, the flow rate of steam generated by the boiler 200, or may detect the load of the boiler 200 based on the amount of power generated by a generator connected to a steam turbine driven by the steam generated by the boiler 200.
The first calculating unit 53 calculates the reference revolution command value Rst of the grinding table 12 corresponding to the load of the boiler 200 detected by the detecting unit 52. Fig. 3 is a diagram showing a relationship between the boiler load and the revolution number command value R when the load of the boiler 200 (boiler load) is increased from the first load L1 to the second load L2. The reference revolution speed command value Rst calculated by the first calculating unit 53 is a value that increases in proportion to the load of the boiler 200 as indicated by a broken line in fig. 3.
The reason why the reference rotation number command value Rst is proportional to the load of the boiler is that the supply amount of the solid fuel supplied from the coal feeder 20 to the solid fuel pulverizer 100 increases in proportion to an increase in the load of the boiler 200, and accordingly, the pressing force of the pulverizing table 12 and the roller 13 is adjusted to increase the rotation number of the pulverizing table 12 in order to optimize the thickness of the solid fuel layer between the pulverizing table 12 and the roller 13 in order to change the pulverizing ability of the solid fuel, and thereby, the delay of the timing of increasing the supply amount of the solid fuel supplied from the solid fuel pulverizer 100 to the boiler 200 (coal output delay) is reduced by suppressing an increase in the mill differential pressure and the occurrence of abnormal vibration due to insufficient pulverization of the mill 10. The first calculation unit 53 stores in advance a table indicating the relationship between the boiler load and the reference revolution command value Rst shown by the broken line in fig. 3 by, for example, performing a test or the like on the solid fuel to be used. Then, first calculating unit 53 refers to the load of boiler 200 detected by detecting unit 52, calculates reference revolution command value Rst, and transmits it to control unit 51.
The second calculating unit 54 calculates the added rotation number command value Rad corresponding to the load of the boiler 200 detected by the detecting unit 52. When a load command for increasing the load of the boiler 200 from the first load L1 to the second load L2 is input to the controller 50 by an operator (not shown), the second calculator 54 calculates the added rotation number command value Rad so as to gradually decrease from the initial value Rad0 to zero in accordance with the increase in the load.
The target revolution number command value Rta shown in fig. 3 is obtained by adding the reference revolution number command value Rst calculated by the first calculating unit 53 and the added revolution number command value Rad calculated by the second calculating unit 54. The target rotation number command value Rta shown by the solid line in fig. 3 shows a change of the rotation number command value R with respect to the boiler load when the load command to increase the load to the second load L2 is input in a state where the first load L1 is detected by the detection portion 52.
As shown in fig. 3, when the 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 an added rotation number command value Rad, and transmits the calculated value Rad to the control unit 51. The controller 51 adds the reference rotation number command value Rst1 calculated by the first calculator 53 for the first load L1 to the initial value Rad0 to calculate the rotation number command value Rta 1. The rotation number command value Rta1 becomes the target rotation number command value Rta at the first load L1.
As shown in fig. 3, the target rotation number command value Rta increases in proportion to the boiler load until the boiler load reaches the second load L2 from the first load L1, and at the second load L2, the target rotation number command value Rta coincides with the reference rotation number command value Rst. This is because the added rotation number command value Rad calculated by the second calculating unit 54 at the second load L2 is zero. In this way, the second calculating unit 54 calculates the added rotation number command value Rad so as to gradually decrease from the initial value Rad0 to zero in accordance with an increase in the load of the boiler 200.
The target rotation number command value Rta is transmitted from the control device 50 to the driving unit 14 to control the rotation number of the grinding table 12. The rotation speed of the grinding table 12 may be controlled by an inverter, for example, by the rotation speed of a drive motor (not shown) of the drive unit 14.
As described above, when the load command for increasing the load of the boiler 200 from the first load L1 to the second load L2 is input, the second calculating unit 54 calculates the added rotation number command value Rad so as to gradually decrease from the initial value Rad0 to zero in accordance with the increase in the load.
Delay of timing when the amount of solid fuel supplied from the solid fuel pulverizer 100 to the boiler 200 increases (coal discharge delay) is reduced, and the load of the boiler does not excessively increase beyond the target load, and the simple addition rotation number command value can be used to improve the following ability to the target load.
On the other hand, when the load command for reducing the load of the boiler 200 from the second load L2 to the first load L1 is input, the second calculation unit 54 calculates the subtraction rotation number command value Rsu so as to gradually decrease from the initial value Rsu0 to zero in accordance with the reduction in the load.
As shown in fig. 4, when a load command for reducing the boiler load to the first load L1 is input in a state where the detector 52 detects the second load L2, the second calculator 54 calculates the initial value Rsu0 as the subtracted rotation number command value Rsu, and transmits the subtracted rotation number command value to the controller 51. The control unit 51 subtracts the initial value Rsu0 from the reference rotation number command value Rst1 for the first load L1 calculated by the first calculation unit 53, and calculates the rotation number command value Rta 2. The rotation number command value Rta2 becomes the target rotation number command value Rta at the second load L2.
As shown in fig. 4, the target rotation number command value Rta is decreased in proportion to the boiler load until the boiler load reaches the first load L1 from the second load L2, and the target rotation number command value Rta coincides with the reference rotation number command value Rst at the first load L1. This is because subtracted revolution number command value Rsu calculated by second calculating unit 54 at first load L1 is zero. In this way, the second calculating unit 54 calculates the subtracted rotation number command value Rsu so as to gradually decrease from the initial value Rsu0 to zero in accordance with the decrease in the load of the boiler 200.
The delay of the timing of the decrease in the amount of solid fuel supplied from the solid fuel pulverizer 100 to the boiler 200 (coal reduction delay) is reduced, and the load of the boiler is not excessively reduced beyond the target load, and the tracking ability with respect to the target load can be improved using a simple subtraction rotation number command value.
That is, the supply amount of the solid fuel supplied from the coal feeder 20 to the solid fuel pulverizer 100 is increased or decreased in proportion to the increase or decrease in the load of the boiler 200, and the delay in the timing of increasing or decreasing the supply amount of the solid fuel supplied from the solid fuel pulverizer 100 to the boiler 200 (coal discharge or coal reduction delay) is reduced by setting the change in the pulverizing capacity of the solid fuel, that is, the revolution number of the pulverizing table 12, to the target revolution number command value Rta obtained by adding the reference revolution number command value Rst to the added revolution number command value Rad or subtracting the subtracted revolution number command value Rsu. Here, it is preferable that the initial value Rad0 of the added rotation number command value Rad calculated by the first calculator 53 when increasing the load of the boiler 200 from the first load L1 to the second load L2 is larger than the initial value Rsu0 of the subtracted rotation number command value Rsu calculated by the first calculator 53 when decreasing the load of the boiler 200 from the second load L2 to the first load L1.
This is because, in order to increase the pulverizing ability of the solid fuel, when the increase in the thickness of the solid fuel layer between the pulverizing table 12 and the roller 13 is suppressed, the pressing force between the pulverizing table 12 and the roller 13 is increased and the number of revolutions of the pulverizing table 12 is increased, which requires time in the step of applying energy. On the other hand, the process of reducing the energy in order to reduce the pulverizing ability of the solid fuel is performed, and therefore, the process of applying energy does not require time to smoothly change the state.
The initial value Rad0 is preferably 1% or more and 30% or less of the reference rotation command value Rst. More preferably, the initial value Rad0 is set to be larger than the initial value Rsu0, in the range of 5% to 25%. The initial value Rsu0 is preferably 1% to 30% of the reference rotation command value Rst. More preferably, 5% or more and 25% or less, and the initial value Rsu0 is set to be smaller than the initial value Rad 0.
The values of the initial values Rad0 and Rsu0 may be the amount of change in load per unit time (the rate of change in boiler load). That is, it is preferable to set the values of the initial values Rad0 and Rsu0 so that the load change rate is different according to the load range of the boiler 200. For example, it is preferable that the initial values Rad0 and Rsu0 are set to a range of a normal operation load change rate in which the rate of change of the boiler load is 3% to 5% per minute when the boiler load is in a range of 30% to 90%, and to a range of, for example, 1% per minute when the boiler load is greater than 90%. The reason for reducing the rate of change in the boiler load when the boiler load is greater than 90% is to avoid an excessive increase in the boiler load beyond the upper limit load, which is caused by an increase in the rate of change in the load in a region where the load is high.
Fig. 5 is a graph showing a temporal change in the coal output from the solid fuel pulverizer 100 to the boiler 200 when the boiler load is increased. In fig. 5, a solid line shows the present embodiment, and shows a temporal change in the coal discharge amount when control device 50 transmits target revolution number command value Rta to drive unit 14. On the other hand, the broken line shows a comparative example of the present embodiment, and shows a temporal change in the coal output amount when the control device 50 transmits only the reference revolution number command value Rst to the drive unit 14. The boiler load at the time t1 is the first load L1, and the time t2 is a state where the boiler load has completed convergence to be stable at the second load L2.
As shown in fig. 5, in the present embodiment, the time taken for the coal output to reach VL2 from VL1 is shorter than in the comparative example, and the responsiveness of the increase in the coal output to the increase in the load of the boiler 200 is high. In the present embodiment, the time until the amount of coal collected when the boiler load became the second load L2, that is, VL2, is shorter than in the comparative example, and the load of the boiler has high followability to the target load.
The operation and effect of the solid fuel pulverizer 100 according to the present embodiment described above will be described.
According to the solid fuel pulverizer 100 of the present embodiment, when a load command for increasing the load of the boiler 200 from the first load L1 to the second load L2 is input, the initial value Rad0 larger than zero is given as the added rotation number command value Rad to the reference rotation number command Rst, and therefore, the responsiveness of the increase in the rotation speed of the pulverizer table 12 to the load command can be improved. Further, since the added rotation number command value Rad gradually decreases from the initial value Rad0 to zero in accordance with the increase in the load, the rotation speed of the grinding table 12 can be set to a speed corresponding to the reference rotation number command value Rst at the time point when the load of the boiler becomes the second load L2. Therefore, the load of the boiler 200 does not excessively increase beyond the target load, and the simple addition rotation number command value Rad can be used to improve the following performance with respect to the target load.
Further, according to the solid fuel pulverizer 100 of the present embodiment, when a load command for reducing the load of the boiler 200 from the second load L2 to the first load L1 is input, the initial value Rsu0 larger than zero is given as the subtraction rotation number command value Rsu to the reference rotation number command value Rst, and therefore, the responsiveness of the reduction in the rotation speed of the pulverizer table 12 to the load command can be improved. Further, since the subtraction rotation number command value Rsu gradually decreases from the initial value Rsu0 to zero in accordance with the decrease in the load, the rotation speed of the grinding table 12 can be set to a speed corresponding to the reference rotation number command value Rst at the time point when the load of the boiler 200 becomes the first load L1. Therefore, the load of the boiler 200 does not excessively decrease beyond the target load, and the simple subtraction rotation number command value Rsu can be used to improve the following performance with respect to the target load.
[ second embodiment ]
Next, a second embodiment of the present application will be explained. The second embodiment is a modification of the first embodiment, is the same as the first embodiment except for the case of the following specific description, and the following description is omitted.
The present embodiment differs from the first embodiment in that the solid fuel pulverizer 100 sets the addition rotation number command value Rad to zero when the load of the boiler 200 detected by the detector 52 is equal to or less than a predetermined load. Fig. 6 is a diagram showing a relationship between the boiler load and the rotation number command value when 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 pulverizer 100 of the second embodiment.
The target revolution number command value Rta shown in fig. 6 is obtained by adding the reference revolution number command value Rst calculated by the first calculating unit 53 and the added revolution number command value Rad calculated by the second calculating unit 54. Target rotation number command value Rta shown by a solid line in fig. 6 shows a change of rotation number command value R with respect to the boiler load when the load command for increasing the load to second load L2 is input in a state where predetermined load L0 is detected by detecting unit 52.
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 added rotation number command value Rad. Therefore, target revolution number command value Rta matches reference revolution number command value Rst in a load range equal to or greater than predetermined load L0 and lower than first load L1 shown in fig. 6. This is because, in a load range lower than the first load L1 (for example, a load with a boiler load of about 30% to 40%), it is not necessary to calculate a value larger than zero as the added rotation number command value Rad, and in this low load range of the boiler load, the added rotation number command value Rad is set to zero, thereby suppressing an excessive increase in the coal output amount due to an excessive increase in the rotation number of the mill table 12 as the reference rotation number command value Rst becomes excessive.
In addition, the delay of the timing of reducing the increase in the supply amount of the solid fuel (coal production delay) can be controlled. 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 in the first embodiment.
In the case where 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 pulverizer 100, zero is calculated as the subtracted revolution command value Rsu in the load range equal to or larger than the predetermined load L0 lower than the first load L1, and the target revolution command value Rta is made to coincide with the reference revolution command value Rst, which is not shown.
[ third embodiment ]
Next, a third embodiment of the present application will be explained. The third embodiment is a modification of the first embodiment, is the same as the first embodiment except for the case of the following specific description, and the following description is omitted.
In the present embodiment, when a load command for increasing 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 added rotation number command value Rad is temporarily set to zero at the second load L2. Fig. 7 is a diagram showing a relationship between the boiler load and the revolution command value R when the boiler load is increased from the first load L1 to the third load L3 in the solid fuel pulverizer 100 of the present embodiment.
In the present embodiment, when a load command for reducing the load of the boiler 200 from the third load L3 to the first load L1 is input, the subtracted rotation number command value Rsu is temporarily set to zero at the second load L2. Fig. 8 is a diagram showing a relationship between the boiler load and the rotation number command value R when the boiler load is decreased from the third load L3 to the first load L1 in the solid fuel pulverizer 100 of the present embodiment.
Here, the operation of the control device 50 when a load command for increasing the load of the boiler 200 from the first load L1 to the third load L3 larger than the second load L2 is input will be described.
The target revolution number command value Rta shown in fig. 7 is obtained by adding the reference revolution number command value Rst calculated by the first calculating unit 53 and the added revolution number command value Rad calculated by the second calculating unit 54. The target rotation number command value Rta shown by the solid line in fig. 7 shows a change of the rotation number command value R with respect to the boiler load when the load command to increase the load to the third load L3 is input in a state where the first load L1 is detected by the detection portion 52.
As shown in fig. 7, when the 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 an added rotation number command value Rad, and transmits the calculated value Rad to the control unit 51. Control unit 51 calculates a rotation number command value Rtal by adding reference rotation number command value Rstl calculated by first calculating unit 53 for first load L1 to an initial value Rad 0. The rotation number command value Rtal becomes the target rotation number command value Rta at the first load L1.
As shown in fig. 7, the target rotation number command value Rta increases in proportion to the boiler load until the boiler load reaches the second load L2 from the first load L1, and at the second load L2, the target rotation number command value Rta coincides with the reference rotation number command value Rst. This is because the added rotation number command value Rad calculated by the second calculating unit 54 at the second load L2 is zero. In this way, the second calculating unit 54 calculates the added rotation number command value Rad so as to gradually decrease from the initial value Rad0 to zero in accordance with an increase in the load of the boiler 200.
As shown in fig. 7, when the detector 52 detects the second load L2, the second calculator 54 calculates an initial value Rad0 as an added rotation number command value Rad, and transmits the calculated value Rad to the controller 51. The controller 51 adds the reference rotation number command value Rst2 calculated by the first calculator 53 for the second load L2 to the initial value Rad0 to calculate the rotation number command value Rta 2. The rotation number command value Rta2 becomes the target rotation number command value Rta at the second load L2.
As shown in fig. 7, the target rotation number command value Rta is increased in proportion to the boiler load until the boiler load reaches the third load L3 from the second load L2, and at the third load L3, the target rotation number command value Rta coincides with the reference rotation number command value Rst. This is because the added rotation number command value Rad calculated by the second calculating unit 54 at the third load L3 is zero. In this way, the second calculating unit 54 calculates the added rotation number command value Rad so as to gradually decrease from the initial value Rad0 to zero in accordance with an increase in the load of the boiler 200.
Next, the operation of the control device 50 when a load command for reducing 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 for reducing the boiler load to the first load L1 is input in a state where the detection unit 52 detects the third load L3, the second calculation unit 54 calculates the initial value Rsu0 as the subtracted rotation number command value Rsu, and transmits the subtracted rotation number command value to the control unit 51. The control unit 51 subtracts the initial value Rsu0 from the reference rotation number command value Rst3 for the third load L3 calculated by the first calculation unit 53, and calculates the rotation number command value Rta 3. The rotation number command value Rta3 becomes the target rotation number command value Rta at the third load L3.
As shown in fig. 8, the target rotation number command value Rta is decreased in proportion to the boiler load until the boiler load reaches the second load L2 from the third load L3, and at the second load L2, the target rotation number command value Rta coincides with the reference rotation number command value Rst. This is because the subtracted rotation number command value Rsu calculated by the second calculating unit 54 at the second load L2 is zero. In this way, the second calculating unit 54 calculates the subtracted rotation number command value Rsu so as to gradually decrease from the initial value Rsu0 to zero in accordance with the decrease in the load of the boiler 200.
As shown in fig. 8, when the detector 52 detects the second load L2, the second calculator 54 calculates the initial value Rsu0 as the subtraction rotation number command value Rsu and transmits the result to the controller 51. The control unit 51 subtracts the initial value Rsu0 from the reference rotation number command value Rst2 for the second load L2 calculated by the first calculation unit 53, and calculates the rotation number command value Rta 2. The rotation number command value Rta2 becomes the target rotation number command value Rta at the second load L2.
As shown in fig. 8, the target rotation number command value Rta is decreased in proportion to the boiler load until the boiler load reaches the first load L1 from the second load L2, and at the first load L1, the target rotation number command value Rta coincides with the reference rotation number command value Rst. This is because subtracted revolution number command value Rsu calculated by second calculating unit 54 at first load L1 is zero. In this way, the second calculating unit 54 calculates the subtracted rotation number command value Rsu so as to gradually decrease from the initial value Rsu0 to zero in accordance with the decrease in the load of the boiler 200.
According to the present 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 added rotation number command value Rad is set to zero at the second load L2, and therefore, the rotation number of the mill table 12 can be prevented from being excessively increased as compared with the case where the added rotation number command value Rad is maintained at a value larger than zero until the third load L3 is reached from the first load L1. Therefore, it is possible to suppress an excessive increase in the amount of coal output with an increase in the number of revolutions of the grinding table 12.
Further, according to the present embodiment, when the load of the boiler 200 is reduced from the third load L3 larger than the second load L2 to the first load L1, the subtraction rotation number command value Rsu is set to zero at the second load L2, and therefore, the rotation number of the grinding table 12 can be prevented from being excessively reduced, as compared with the case where the subtraction rotation number command value Rsu is maintained at a value larger than zero until the third load L3 reaches the first load L1. Therefore, the coal output amount can be suppressed from excessively decreasing with a decrease in the number of revolutions of the grinding table 12.
[ fourth embodiment ]
Next, a fourth embodiment of the present application will be explained. The fourth embodiment is a modification of the first embodiment, is the same as the first embodiment except for the case of the following specific description, and the following description is omitted.
In the first embodiment, the initial value Rad0 of the command added rotational number Rad and the initial value Rsu0 of the command subtracted rotational number Rsu are set to be fixed values regardless of the range of the boiler load or set to be different values depending on the range of the boiler load.
In contrast, in the present embodiment, the initial values Rad0 and Rsu0 are set as a function of the amount of change in the load of the boiler 200 per unit time (boiler change rate). Fig. 9 is a graph showing a relationship between the rate of change of the boiler load and the initial value Rad0 of the added rotation number command value Rad and the initial value Rsu0 of the subtracted rotation number command value Rsu in the solid fuel pulverizer 100 of the fourth embodiment.
As shown in fig. 9, the initial value Rad0 of the added rotation number command value Rad is set by a linear function that increases in proportion to an increase in the rate of change in the boiler load. That is, when the load command for increasing the load of the boiler 200 is input, the second calculation unit 54 sets the initial value Rad0 according to the amount of increase in 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, it is possible to set an appropriate initial value Rad0 in accordance with the amount of increase in load per unit time using a simple linear function, and it is possible to improve the following ability of the number of revolutions of the grinding table 12 to changes in load of the boiler 200 and to suppress an excessive increase in the number of revolutions of the grinding table 12 and an excessive increase in the coal output.
Further, the initial value Rsu0 of the subtracted revolution number command value Rsu is set by a linear function that increases in proportion to an increase in the rate of change in the boiler load. That is, when the load command for reducing the load of the boiler 200 is input, the second calculation unit 54 sets the initial value Rsu0 in accordance with the amount of reduction in the load of the boiler 200 per unit time. By setting the initial value Rsu0 in accordance with the amount of reduction in the load per unit time, an appropriate initial value Rsu0 in accordance with the amount of reduction in the load per unit time can be set using a simple linear function, so that the ability of the number of revolutions of the grinding table 12 to follow changes in the load of the boiler 200 can be improved, and excessive reduction in the number of revolutions of the grinding table 12 and excessive reduction in the coal output can be suppressed.
In the case where the increase and decrease in the boiler load are changed at the same rate of change in the boiler load as in the first embodiment, the initial value Rad0 is preferably larger than the initial value Rsu 0.
Claims (9)
1. A solid fuel pulverizer for pulverizing a solid fuel and feeding the pulverized solid fuel to a boiler,
the solid fuel pulverizer includes:
a crushing workbench;
a driving unit that generates a driving force for rotating the mill table;
a roller that pulverizes the solid fuel supplied from a fuel supply section to the pulverization table between the roller and the pulverization table;
a classifying section that classifies the solid fuel pulverized by the roller into a fine powder fuel having a particle size smaller than a predetermined particle size and carries the fine powder fuel out of the solid fuel pulverizing apparatus;
a first calculation unit that calculates a reference rotation number command value of the grinding table according to a load of the boiler;
a second calculating unit that calculates an added rotation number command value of the grinding table according to the load; and
a control unit for controlling the rotation number of the grinding table driven by the driving unit based on a target rotation number command value obtained by adding the reference rotation number command value and the added rotation number command value,
when a load command for increasing the load of the boiler from a first load to a second load is input, the second calculation unit gradually decreases the added rotation number command value from an initial value to zero in accordance with an increase from the first load to the second load.
2. The solid fuel pulverizing apparatus according to claim 1,
when a load command for increasing the load of the boiler from the first load to a third load larger than the second load is input, the second calculation unit gradually decreases the added rotation number command value from the initial value to zero in accordance with an increase from the first load to the second load, and gradually decreases the added rotation number command value from the initial value to zero in accordance with an increase from the second load to the third load.
3. The solid fuel pulverizing apparatus according to claim 1 or 2, wherein,
the second calculation unit sets the initial value in accordance with an increase in the load per unit time.
4. The solid fuel pulverizing apparatus according to claim 1 or 2, wherein,
the second calculating unit sets the added rotation command value to zero when the load is lower than a predetermined load.
5. The solid fuel pulverizing apparatus according to claim 1,
the second calculating unit calculates a subtraction rotation number command value of the grinding table corresponding to the load,
when a load command for reducing the load of the boiler from the second load to the first load is input, the second calculation unit gradually reduces the subtracted rotation number command value from the initial value to zero in accordance with a reduction from the second load to the first load.
6. The solid fuel pulverizing apparatus according to claim 5,
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 second calculation unit gradually reduces the subtraction rotation number command value from the initial value to zero in accordance with a reduction from the third load to the second load, and gradually reduces the subtraction rotation number command value from the initial value to zero in accordance with a reduction from the second load to the first load.
7. The solid fuel pulverizing apparatus according to claim 5 or 6,
the second calculation unit sets the initial value in accordance with a decrease amount of the load per unit time.
8. A method for controlling a solid fuel pulverizer for pulverizing a solid fuel and feeding the pulverized solid fuel to a boiler, wherein,
the solid fuel pulverizer includes:
a crushing workbench;
a driving unit that generates a driving force for rotating the mill table;
a roller that pulverizes the solid fuel supplied from a fuel supply portion to the pulverization table between the roller and the pulverization table; and
a classifying section that classifies the solid fuel pulverized by the roller into a fine powder fuel having a particle size smaller than a predetermined particle size and carries the fine powder fuel out of the solid fuel pulverizing apparatus,
the control method includes:
a first calculation step of calculating a reference revolution command value of the grinding table according to a load of the boiler;
a second calculating step of calculating an added rotation number command value of the grinding table corresponding to the load; and
a control step of controlling the number of revolutions of the grinding table driven by the drive unit based on a target revolution command value obtained by adding the reference revolution command value and the added revolution command value,
when a load command for increasing the load of the boiler from a first load to a second load is input, the second calculation step gradually decreases the added rotation number command value from an initial value to zero in accordance with an increase from the first load to the second load.
9. The control method of a solid fuel pulverizing apparatus according to claim 8, wherein,
the control method includes a third calculating step of calculating a subtraction rotation command value corresponding to the load,
when a load command for reducing the load of the boiler from a second load to a first load is input, in the third calculation step, the subtracted rotation number command value is gradually reduced from the initial value to zero in accordance with a reduction from the second load to the first load.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017-193325 | 2017-10-03 | ||
| JP2017193325A JP7039805B2 (en) | 2017-10-03 | 2017-10-03 | Solid fuel crusher |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109622148A CN109622148A (en) | 2019-04-16 |
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| CN113939367B (en) * | 2019-06-14 | 2023-04-04 | 古河机械金属株式会社 | Method for producing inorganic material and apparatus for producing inorganic material |
| JP7330786B2 (en) * | 2019-07-05 | 2023-08-22 | 川崎重工業株式会社 | Method for operating pulverization system and method for producing powder |
| CN110552813B (en) * | 2019-08-28 | 2024-05-03 | 中南大学 | Rotary cutting type powder supply system and powder fuel ramjet engine thereof |
| CN111911950B (en) * | 2020-08-14 | 2022-12-16 | 中国神华能源股份有限公司国华电力分公司 | Boiler water-cooling wall temperature control method and device and electronic equipment |
| CN112354672B (en) * | 2020-10-16 | 2022-09-20 | 内蒙古京能康巴什热电有限公司 | Control method for output of coal mill in ignition process of boiler |
| CN113852096B (en) * | 2021-09-03 | 2024-08-09 | 国网新疆电力有限公司电力科学研究院 | Supercritical frequency modulation peak regulation thermal power unit coal quantity instruction optimization method |
| CN115301392B (en) * | 2022-07-08 | 2024-06-07 | 浙江浙能技术研究院有限公司 | Continuous loading control method based on variable-speed coal mill |
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| JP2019066121A (en) | 2019-04-25 |
| CN109622148A (en) | 2019-04-16 |
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