JP2021121424A - Discharge device, solid fuel crushing device and boiler system, and operation method of discharge device - Google Patents

Abstract

To inhibit closure of a discharge device.SOLUTION: A discharge device 60 discharges a fine particle fuel from an opening 11e formed at a housing 11 forming an outer shell. The discharge device 60 includes: a spillage chute 73 which is provided below the opening 11e and communicates with the opening 11e and in which the fine particle fuel discharged from the opening 11e circulates; and an assist gas jet part 74 which is provided within the spillage chute 73 and jets an assist gas into the spillage chute 73. The assist gas jet part 74 is provided at a position located below the opening 11e and on the outer side of the opening 11e when the opening 11e is viewed in a plan view.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a discharge device, a solid fuel crusher and a boiler system, and a method of operating the discharge device.

Conventionally, in a thermal power plant, solid fuel (carbon-containing solid fuel) such as coal or biomass fuel is crushed into fine powder within a predetermined particle size range by a crusher (mill) and supplied to a combustion apparatus. The mill crushes solid fuel such as coal and biomass fuel charged into the rotary table by chewing it between the rotary table and rollers, and is crushed by the transport gas supplied from the outer circumference of the rotary table to form a fine powder. The fuel is classified by a classifier to select fine powder fuel in a predetermined particle size range, transported to a boiler, and burned by a combustion device. In a thermal power plant, steam is generated by heat exchange with the combustion gas generated by burning in a boiler, the steam turbine is rotationally driven by the steam, and the generator connected to the steam turbine is rotationally driven to generate electricity. Is done.

When the crusher is stopped, the crushed solid fuel remaining inside the crusher housing (for example, in the case of coal, residual coal) to prevent the solid fuel inside the housing from igniting when restarted. Also called) needs to be discharged. At the time of normal stop, the rotary table is rotated while supplying the transport gas for a certain period of time after the coal supply is stopped, and the purge operation is performed to discharge the solid fuel remaining inside the housing to the combustion device. On the other hand, when the crusher is urgently stopped due to a trouble or the like, it is necessary to discharge the residual coal from the housing by a clearing operation or the like. In the clearing operation, the rotary table is rotated without supplying a transport gas, and the residual coal on the rotary table is dropped onto the bottom plate (bottom surface) of the housing by centrifugal force, and on the bottom surface of the housing. By a scraper that rotates and moves, the solid fuel that has fallen and accumulated on the bottom surface is guided to the opening formed on the bottom surface, and is discharged from this opening to the spirage hopper via the spillage chute. be.

In the spillage chute, it is necessary to surely discharge solid fuel etc. to the spillage hopper. Therefore, a crusher in which an air nozzle is provided in the spirage chute is known in order to suppress clogging of solid fuel or the like in the spillage chute (for example, Patent Document 1). Patent Document 1 describes a crusher provided with an air nozzle inside the spirage chute.

Jikkenhei No. 4-26035

At the time of emergency stop of the crusher, inert steam may be introduced into the mill to prevent the temperature rise due to natural oxidation of the crushed solid fuel remaining inside the crusher housing. When the solid fuel, etc. is discharged from the opening at the bottom of the crusher to the spirage hopper by the spillage chute due to the moisture of the injected inert steam or the moisture originally contained in the solid fuel, the solid fuel, etc. May be in a state where it easily adheres to the wall surface or the like. Therefore, the solid fuel or the like that has flowed into the spillage chute may adhere to or accumulate on the inner surface of the spillage chute, blocking the spillage chute. If the spillage chute is blocked and a defective discharge of solid fuel or the like occurs, there is a possibility that the operation at the time of restarting the crusher may be hindered, and a new process for eliminating the blockage is required.

In the crusher of Patent Document 1, in order to suppress the blockage of solid fuel or the like in the spirage chute, an air nozzle is formed in a region vertically below the foreign matter discharge port (opening formed in the bottom surface) in the lower chamber of the table of the housing. Is provided. As a result, foreign matter and solid fuel that have flowed into the spillage chute from the opening are promoted to be discharged by eliminating the blockage of the foreign matter and the solid fuel in the spillage chute by the air ejected from the air nozzle. The part falls on the top of the air nozzle. Therefore, solid fuel or the like that has fallen on the air nozzle may be deposited on the air nozzle. When solid fuel or the like is deposited on the air nozzle, the accumulated solid fuel or the like becomes large starting from the deposited solid fuel or the like, and there is a possibility that the spillage chute is blocked by the solid fuel or the like.

The present disclosure has been made in view of such circumstances, and an object of the present invention is to provide a discharge device, a solid fuel crusher and a boiler system, and an operation method of the discharge device capable of suppressing blockage of the discharge device. And.

In order to solve the above problems, the following means are adopted for the operation method of the discharge device, the solid fuel crusher and the boiler system, and the discharge device of the present disclosure.
The discharge device according to one aspect of the present disclosure is a discharge device that discharges the crushed solid fuel from an opening provided in a housing forming the outer shell of a crusher that crushes the solid fuel, and is below the opening. A duct that communicates with the opening and allows the crushed solid fuel discharged from the opening to flow, and an injection unit that is provided inside the duct and injects fluid into the inside of the duct. The injection portion is provided below the opening and outside the opening when the opening is viewed in a plan view.

The operation method of the discharge device according to one aspect of the present disclosure is the operation method of the discharge device that discharges the crushed solid fuel from the opening provided in the housing forming the outer shell of the crusher that crushes the solid fuel. The discharge device is provided below the opening, communicates with the opening, and has a flat surface with a duct through which the crushed solid fuel discharged from the opening flows and inside the duct. It is provided on the outside of the opening when viewed, and has an injection unit for injecting a fluid into the inside of the duct, and includes an injection step for injecting the fluid from the injection unit.

According to the present disclosure, blockage of the discharge device can be suppressed.

It is a schematic block diagram of the boiler system which concerns on embodiment of this disclosure. It is a schematic vertical sectional view of the solid fuel crushing apparatus of FIG. It is a schematic vertical sectional view which shows the discharge device of the solid fuel crusher of FIG. It is a schematic plan view which shows the opening and the assist gas injection part formed in the solid fuel crushing apparatus of FIG. It is a side view which shows the flange joint of FIG. 4A. It is a schematic vertical sectional view which shows the discharge device of the solid fuel crusher of FIG. 2, and shows the relationship between the position at an opening and the discharge amount of residual coal. It is a schematic block diagram which shows the supply pipe of the discharge device of this disclosure. It is a graph which shows the relationship between the injection amount of the assist gas of the discharge device of FIG. 6A, and the mill load. It is a figure which shows the modification of FIG. 6A. It is a graph which shows the relationship between the injection amount of the assist gas of the discharge device of FIG. 7A, and the mill load. It is a schematic block diagram which shows the supply pipe of the discharge device of this disclosure, and is the figure which shows the modification of FIG. 6A. It is a graph which shows the relationship between the injection amount of the assist gas of the discharge device of FIG. 8A, and the mill load. It is a schematic vertical sectional view which shows the modification of FIG. It is a schematic vertical sectional view which shows the modification of FIG. It is a schematic vertical sectional view which shows the modification of FIG.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
The boiler system 1 according to the present embodiment includes a solid fuel crushing device 100 and a boiler 200.

As shown in FIG. 1, the solid fuel crusher 100 of the present embodiment crushes a solid fuel (carbon-containing solid fuel) such as coal or biomass fuel as an example to generate pulverized fuel, and burner portion (burner portion) of the boiler 200 ( Combustion device) A device that supplies 220. The boiler system 1 including the solid fuel crushing device 100 and the boiler 200 shown in FIG. 1 includes one solid fuel crushing device 100, and corresponds to each of the plurality of burner portions 220 of the one boiler 200. The system may be provided with a plurality of solid fuel crushers 100.

The solid fuel crusher 100 of the present embodiment includes a mill (crusher) 10, a coal feeder 20, a blower 30, a state detection unit 40, a control unit 50, and a discharge device 60.
In the present embodiment, "upper" means the direction of the vertically upper side, and "upper" such as the upper part and the upper surface means the part on the vertically upper side. Similarly, "lower" indicates a portion on the vertical lower side, and the vertical direction is not strict and includes an error.

The mill 10 for crushing solid fuel such as coal or biomass fuel supplied to the boiler 200 into pulverized solid fuel, which is a pulverized solid fuel, may be in the form of crushing only coal or pulverizing only biomass fuel. It may be in the form of crushing biomass fuel together with coal.
Here, the biomass fuel is a renewable organic resource derived from living organisms, for example, thinned wood, waste wood, drifting wood, grass, waste, sludge, tires, and recycled fuel (pellets and pellets) made from these. Chips), etc., and are not limited to those presented here. Since biomass fuel takes in carbon dioxide during the growth process of biomass, it is considered to be carbon-neutral, which does not emit carbon dioxide, which is a greenhouse gas, and its use is being studied in various ways.

As shown in FIGS. 1 and 2, the mill 10 includes a housing 11 forming an outer shell, a rotary table 12, a roller 13, a drive unit 14, a rotary classifier 16, and a fuel supply unit. A motor 18 for rotationally driving the rotary classifier 16 and a scraper 70 for discharging deposits accumulated on the bottom surface 11d of the housing 11 are provided.
The housing 11 is formed in a tubular shape extending in the vertical direction, and is a housing that houses a rotary table 12, a roller 13, a rotary classifier 16, and a fuel supply unit 17. The inner peripheral surface 11a of the housing 11 has a substantially cylindrical shape, and the central axis C1 (see FIG. 2) extending in the vertical direction of the housing 11 is substantially one with the central axis C1 of the rotary table 12 and the rotary classifier 16 described later. I am doing it.
A fuel supply unit 17 is attached to the central portion of the ceiling portion 42 of the housing 11. The fuel supply unit 17 supplies the solid fuel guided from the bunker 21 into the housing 11, is arranged at the center position of the housing 11 in the vertical direction, and the lower end portion extends to the inside of the housing 11. ing.

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

When the solid fuel is charged from the fuel supply unit 17 toward the substantially central region of the rotary table 12, the solid fuel is guided to the outer peripheral side of the rotary table 12 by the centrifugal force due to the rotation of the rotary table 12, and is connected to the roller 13. It is sandwiched between them and crushed. The crushed solid fuel is blown upward by the transport gas (hereinafter referred to as primary air) guided from the transport gas flow path (hereinafter referred to as primary air flow path) 100a, and rotates. It is led to the formula classifier 16. The primary air flow path 100a supplies the primary air into the housing 11 below the rotary table 12 via a primary air duct (conveying gas supply duct) 27 (see FIG. 2) connected to the housing 11. ..
An outlet 25 (see FIG. 2) is provided on the outer periphery of the rotary table 12 to allow the primary air flowing from the primary air flow path 100a through the primary air duct 27 to flow out to the space above the rotary table 12 in the housing 11. Has been done. A vane 26 (see FIG. 2) is installed in the vicinity of the air outlet 25 to give a swirling force to the primary air blown out from the air outlet 25. The primary air to which the swirling force is applied by the vane 26 becomes an air flow having a swirling velocity component, and guides the solid fuel crushed on the rotary table 12 to the upper rotary classifier 16 in the housing 11. Of the crushed solid fuel mixed in the primary air, those having a particle size larger than the predetermined particle size are classified by the rotary classifier 16 or fall down without reaching the rotary classifier 16 to reach the rotary table. It is returned to 12 and crushed again with the roller 13.

The roller 13 is a rotating body that crushes the solid fuel supplied from the fuel supply unit 17 to the rotary table 12. The roller 13 is pressed against the upper surface of the rotary table 12 and cooperates with the rotary table 12 to crush the solid fuel.
In FIG. 1, only one roller 13 is represented as a representative, but a plurality of rollers 13 are arranged to face each other at regular intervals in the circumferential direction so as to press the upper surface of the rotary table 12. NS. For example, the three rollers 13 are arranged at equal intervals in the circumferential direction with an angular interval of 120 ° on the outer peripheral portion. In this case, the portion where the three rollers 13 are in contact with the upper surface of the rotary table 12 (the portion to be pressed) is equidistant from the rotation central axis (central axis C1) of the rotary table 12.

The roller 13 can be swung up and down by the journal head 45, and is supported so as to be close to and separated from the upper surface of the rotary table 12. When the rotary table 12 rotates with the outer peripheral surface in contact with the solid fuel on the upper surface of the rotary table 12, the roller 13 receives rotational force from the rotary table 12 and rotates around the roller 13. When the solid fuel is supplied from the fuel supply unit 17, the solid fuel is pressed between the roller 13 and the rotary table 12 and crushed to become fuel after crushing.

The support arm 47 of the journal head 45 is supported by a support shaft 48 whose intermediate portion is along the horizontal direction on the side surface portion 11b of the housing 11 so as to be swingable in the vertical direction of the roller 13 about the support shaft 48. Further, a pressing device 49 is provided at the upper end portion on the vertically upper side of the support arm 47. The pressing device 49 is fixed to the housing 11 and applies a load to the roller 13 via the support arm 47 or the like so as to press the roller 13 against the rotary table 12.

The drive unit 14 is a device that transmits a driving force to the rotary table 12 and rotates the rotary table 12 around the central axis C1. The drive unit 14 generates a driving force for rotating the rotary table 12.

The rotary classifier 16 is provided on the upper part of the housing 11 and has a hollow substantially inverted conical outer shape. The rotary classifier 16 includes a plurality of blades 16a extending in the vertical direction at its outer peripheral position. Each blade 16a is provided around the central axis C1 of the rotary classifier 16 at a predetermined interval (equal interval). Further, the rotary classifier 16 uses a solid fuel crushed by the roller 13 having a size larger than a predetermined particle size (for example, 70 to 100 μm for coal) (hereinafter, crushed solid fuel exceeding a predetermined particle size as “coarse powder”. It is a device that classifies fuel into (referred to as "fuel") and fuel having a predetermined particle size or less (hereinafter, crushed solid fuel having a predetermined particle size or less is referred to as "fine powder fuel"). The rotary classifier 16 that classifies by rotation is also called a rotary separator, and is given a rotational driving force by a motor 18 controlled by a control unit 50 to provide a cylindrical shaft (not shown) extending in the vertical direction of the housing 11. It rotates around the fuel supply unit 17 in the center.

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

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

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

The blower portion 30 dries the solid fuel crushed by the rollers 13 and supplies the primary air (also referred to as “conveying air” in the following description) to the inside of the housing 11 for supplying the rotary classifier 16. It is a device that blows air.
In this embodiment, the blower unit 30 cools the primary air ventilator (PAF: Primary Air Fan) 31, the hot gas flow path 30a, and the cold gas flow path 30a in order to adjust the primary air blown to the housing 11 to an appropriate temperature. It includes a gas flow path 30b, a hot gas damper 30c, and a cold gas damper 30d.

In the present embodiment, the heat gas flow path 30a heats a part of the air (outside air) sent from the primary air ventilator 31 through a heat exchanger (heater) 34 such as an air preheater. It is supplied as heat gas. A hot gas damper 30c (first blower portion) is provided on the downstream side of the hot gas flow path 30a. The opening degree of the hot gas damper 30c is controlled by the control unit 50. The flow rate of the hot gas supplied from the hot gas flow path 30a is determined by the opening degree of the hot gas damper 30c.

The cold gas flow path 30b supplies a part of the air sent out from the primary air ventilator 31 as cold gas at room temperature. A cold gas damper (second blower) 30d is provided on the downstream side of the cold gas flow path 30b. The opening degree of the cold gas damper 30d is controlled by the control unit 50. The flow rate of the cold gas supplied from the cold gas flow path 30b is determined by the opening degree of the cold gas damper 30d.

In the present embodiment, the flow rate of the primary air is the total flow rate of the hot gas supplied from the hot gas flow path 30a and the cold gas flow rate supplied from the cold gas flow path 30b, and is the solid fuel supplied to the mill 10. It is controlled by the control unit 50 according to the supply amount (coal supply amount) of. The temperature of the primary air is determined by the mixing ratio of the hot gas supplied from the hot gas flow path 30a and the cold gas supplied from the cold gas flow path 30b, and is controlled by the control unit 50.
Further, a part of the combustion gas discharged from the boiler 200 is guided to the hot gas supplied from the hot gas flow path 30a via a gas recirculation ventilator (not shown) to form an air-fuel mixture, thereby forming the primary air flow path 100a. The oxygen concentration of the primary air flowing in from may be adjusted.

In the present embodiment, the state detection unit 40 of the mill 10 transmits the measured or detected data to the control unit 50. The state detection unit 40 of the present embodiment is, for example, a differential pressure measuring means, and is a portion where the primary air flows from the primary air flow path 100a into the mill 10 and the primary air and fine powder fuel from the inside of the mill 10 into the supply flow path 100b. The differential pressure with the outlet 19 discharged from the mill 10 is measured as the differential pressure in the mill 10. For example, depending on the classification performance of the rotary classifier 16, the increase / decrease in the circulation amount of the crushed solid fuel that circulates inside the mill 10 between the vicinity of the rotary classifier 16 and the vicinity of the rotary table 12 and the difference in the mill 10 with respect to this. The increase and decrease of pressure changes. That is, since the pulverized fuel discharged from the outlet 19 can be adjusted and managed with respect to the solid fuel supplied to the inside of the mill 10, the particle size of the pulverized fuel does not affect the combustibility of the burner portion 220. The amount of pulverized fuel corresponding to the amount of solid fuel supplied to the mill 10 can be stably supplied to the burner portion 220 provided in the boiler 200.
Further, the state detection unit 40 of the present embodiment is, for example, a temperature measuring means, and is the temperature of the primary air supplied to the inside of the housing 11 for blowing the solid fuel crushed by the roller 13 to the rotary classifier 16. , The temperature of the primary air up to the outlet 19 is detected inside the housing 11, and the blower portion 30 is controlled so as not to exceed the upper limit temperature. Since the primary air is cooled by transporting the crushed material while drying it in the housing 11, the temperature from the upper space of the housing 11 to the outlet 19 is, for example, about 60 to 80 degrees.

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

The control unit 50 is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. Then, as an example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is installed in a ROM or other storage medium in advance, is provided in a state of being stored in a computer-readable storage medium, or is distributed via a wired or wireless communication means. Etc. may be applied. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like.

Next, the boiler 200 that burns using the fine fuel supplied from the solid fuel crusher 100 to generate steam will be described.
As shown in FIG. 1, the boiler 200 includes a furnace 210 and a burner portion 220.

The burner unit 220 heats the primary air containing the fine fuel supplied from the supply flow path 100b and the air (outside air) sent from the indented air ventilator (FDF: Feed Draft Fan) 32 by the heat exchanger 34. It is a device that forms a flame by burning fine fuel using the supplied secondary air. The pulverized fuel is burned in the furnace 210, and the high-temperature combustion gas is discharged to the outside of the boiler 200 after passing through heat exchangers (not shown) such as an evaporator, a superheater, and an economizer.

The combustion gas discharged from the boiler 200 is subjected to a predetermined treatment by an environmental device (not shown by a denitration device, an electrostatic collector, etc.), and is sent from the primary air ventilator 31 by a heat exchanger 34 such as an air preheater, for example. Heat exchange is performed between the air and the air sent from the indented air blower 32, and the air is guided to the chimney (not shown) via the induced blower (IDF) 33 and discharged to the outside air. NS. The air sent from the primary air ventilator 31 heated by the combustion gas in the heat exchanger 34 is supplied to the hot gas flow path 30a described above.
The water supply to each heat exchanger of the boiler 200 is heated in a coal saver (not shown) and then further heated by an evaporator (not shown) and a superheater (not shown) to generate high-temperature and high-pressure steam. , The steam turbine is sent to the steam turbine (not shown), which is a power generation unit, to rotate drive the steam turbine, and the generator connected to the steam turbine (not shown) is rotationally driven to generate power, thereby forming the boiler system 1. ..

Next, the scraper (sweep section) 70 will be described. The scraper 70 is arranged below the rotary table 12 as shown in FIG. The scraper 70 has an arm portion 71 whose one end is fixed to the rotary table 12 and a moving portion extending vertically downward from the free end portion (the end opposite to the end portion fixed to the rotary support portion) of the arm portion 71. 72 and. The scraper 70 can rotate coaxially with the rotary table 12. That is, the scraper 70 rotates about the central axis C1. In this embodiment, it is rotated clockwise in top view (see also arrow R in FIG. 4A). The arm portion 71 extends substantially horizontally in the direction of the side surface portion 11b of the housing 11. The moving portion 72 is arranged so that the lower end abuts on the bottom surface portion 11d of the housing 11, and slides on the upper surface of the bottom surface portion 11d.
Further, an opening 11e is formed on the rotation track of the moving portion 72, which is the bottom surface portion 11d of the housing 11. As shown in FIGS. 3 and 4, the opening 11e is a hole penetrating in the vertical direction, and in the present embodiment, the opening 11e has, for example, a quadrangular shape in a plan view. The opening 11e is provided outside the central axis C1 in the radial direction. The scraper 70 guides the crushed fuel deposited on the bottom surface 11d to the opening 11e.

As shown in FIGS. 2 and 3, a discharge device 60 is provided below the opening 11e. The discharge device 60 includes a spillage chute (duct) 73 whose upstream end communicates with the opening 11e, an assist gas injection section (injection section) 74 provided inside the spillage chute 73 to inject assist gas, and a spillage chute. It includes a spirage hopper 75 that connects to the downstream end of 73.

As shown in FIG. 3, the spirage chute 73 is a duct-shaped member provided below the opening 11e. The pulverized fuel that has flowed into the spirage chute 73 through the opening 11e (in the following description, the pulverized solid fuel remaining inside the housing 11 is also referred to as “residual coal”. .) Is distributed. The spirage chute 73 is tilted so as to have a predetermined angle with respect to the horizontal plane. Specifically, the spirage chute 73 is formed so as to be inclined with respect to the horizontal plane in substantially the entire longitudinal region and not to have a portion extending in the vertical direction. The predetermined angle is set to be an angle equal to or higher than the angle of repose of the fuel after crushing. As a result, the residual coal, which is the fuel after crushing, preferably slides down on the bottom surface 73d of the spirage chute 73, so that clogging of the spirage chute 73 can be suppressed. A sluice valve 76 is provided in the middle of the spillage chute 73. The residual coal is a name for convenience, and the solid fuel is not limited to coal.

The spirage chute 73 has an inlet opening 73a formed at the upstream end in the residual coal flow and an outlet opening 73b formed at the downstream end in the residual coal flow. Further, the spirage chute 73 has a flange portion 73c protruding outward from the outer peripheral surface of the upstream end portion.

As shown in FIG. 3, the entrance opening 73a communicates with the opening 11e from below. As shown in FIGS. 3 and 4, the entrance opening 73a is a hole penetrating in the vertical direction and has a quadrangular shape in a plan view. The entrance opening 73a is formed larger than the opening 11e formed in the bottom surface portion 11d of the housing 11. The entrance opening 73a is formed so as to be larger than the opening 11e. Further, the entrance opening 73a and the opening 11e are arranged so that all of the opening 11e overlaps with the entrance opening 73a when the entrance opening 73a is viewed from above. That is, all the edges of the inlet opening 73a are located outside the edges of the opening 11e.

The outlet opening 73b is a circular opening that communicates with the upper part of the spirage hopper 75.
The flange portion 73c is a plate-shaped member. The flange portion 73c is a quadrangular frame-shaped member provided over the entire circumferential direction of the spirage chute 73. The upper surface of the flange portion 73c may be connected to the lower surface of the bottom surface portion 11d of the housing 11 in surface contact, or a part of the area or the lower surface of the bottom surface portion 11d of the connection flange portion 90 may be connected. The entire area may be connected via a sealing member. A plurality of through holes penetrating in the vertical direction are formed in the flange portion 73c. The plurality of through holes are formed side by side at predetermined intervals in the circumferential direction, and are fixed to the bottom surface portion 11d of the housing 11 by bolts 73e through which the through holes are inserted.

The assist gas injection unit 74 is provided inside the spirage chute 73, and injects the assist gas into the spirage chute 73. In this embodiment, for example, air can be used as the assist gas. Further, dry steam, an inert gas such as nitrogen gas or carbon dioxide can be used. When an inert gas is used, spontaneous combustion of residual coal, which is a fuel after crushing, can be suppressed. Further, when the discharge device 60 is a wet recovery method using water, water, steam, or the like may be injected instead of the assist gas. In this case, if water is sprayed to clear the blockage and then the spraying is stopped, dry residual coal may be deposited again due to the water remaining on the inner wall of the spirage chute 73. A liquid such as water may be sprayed at all times even during normal operation.

As shown in FIG. 4A, the assist gas injection unit 74 includes an injection pipe 77 for injecting the assist gas, and a supply pipe 78 for supplying the assist gas supplied from the assist gas supply device (not shown) to the injection pipe 77. It has two flange joints 79 that connect the injection pipe 77 and the supply pipe 78. The assist gas injection unit 74 injects the assist gas from the vicinity of the bottom surface 73d of the spillage chute 73 toward the outlet opening 73b, and the residual coal accumulated on the bottom surface 73d is injected from the outlet opening 73b to the inside of the spillage hopper 75. Discharge toward.

As shown in FIG. 3, the injection pipe 77 is arranged near the bottom surface 73d of the spirage chute 73. Further, the injection pipe 77 is provided below the opening 11e and outside the opening 11e when the opening 11e is viewed in a plan view. That is, the injection pipe 77 is not provided vertically below the opening 11e, but is provided vertically below the bottom surface portion 11d of the housing 11. The injection pipe 77 is arranged in the vicinity of the inlet opening 73a of the spirage chute 73. That is, the injection pipe 77 of the assist gas injection unit 74 is not provided in the region vertically below the opening 11e. As a result, the residual coal that has flowed into the spirage chute 73 through the opening 11e is less likely to come into contact with or accumulate on the upper portion of the assist gas injection portion 74.

As shown in FIG. 4A, the injection pipe 77 penetrates the side wall of the spirage chute 73 and extends linearly in the width direction of the spirage chute 73. The injection pipe 77 extends along the rotation direction R of the scraper 70. Assist gas is introduced inside the injection pipe 77.

Further, a plurality of injection holes 77a (7 in this embodiment as an example) are formed on the side surface of the injection pipe 77 on the outlet opening 73b side. The plurality of injection holes 77a are arranged side by side at predetermined intervals (approximately equal intervals in the present embodiment) along the extending direction of the injection pipe 77. Each injection hole 77a injects the assist gas that is introduced into the injection pipe 77 and circulates in the injection pipe 77.

The injection pipe 77 injects the assist gas in the direction of the outlet opening 73b of the spirage chute 73 (see arrow A in FIGS. 3 and 5). Specifically, as shown in FIG. 5, the injection pipe 77 is a region of the bottom surface 73d of the spirage chute 73 that is radially outer of the central axis C2 of the opening 11e with respect to the central axis C1 of the housing 11. Assist gas is injected toward. The graph of FIG. 5 shows the relationship between the radial position of the opening 11e and the amount of residual coal discharged at the position. The residual coal discharge amount indicates the residual coal amount discharged by the scraper 70 from the opening 11e. As shown in FIG. 5, the residual coal discharge amount increases from the inner end in the radial direction toward the central axis C2, and the residual coal discharge amount becomes the largest at the position P1 on the outer side in the radial direction from the central axis C2. ing. Further, with the position P1 as the peak, the amount of residual coal discharged decreases toward the outer end in the radial direction. In the present embodiment, the assist gas is injected toward the target point P2 located vertically below the position P1 where the residual coal discharge amount is the largest in the radial direction of the opening 11e.

A supply pipe 78 is connected to the end of the injection pipe 77 on the rear side (upstream side) of the scraper 70 in the rotation direction R via a flange joint 79. Therefore, in the plurality of injection holes 77a, the injection pressure of the assist gas is larger as the injection holes 77a on the supply pipe 78 side. That is, the injection holes 77a arranged on the rear side (upstream side) in the rotation direction R of the scraper 70 inject the assist gas more than the injection holes 77a arranged on the front side (downstream side) in the rotation direction R. The pressure is increasing.
Since the scraper 70 passes above the opening 11e, the residual coal guided to the opening 11e by the scraper 70 is on the rear side (upstream side, in other words, the lower side of the paper surface of FIG. 4A) in the rotation direction R of the opening 11e. The residual coal begins to fall into the opening 11e. Therefore, the amount of residual coal flowing into the spirage chute 73 from the opening 11e is larger on the rear side (upstream side) in the rotation direction R of the scraper 70 than on the front side (downstream side). Therefore, it is preferable because the ejection pressure of the assist gas can be increased toward the side where the amount of residual coal discharged increases.

The supply pipe 78 supplies the assist gas from the assist gas supply device (not shown) to the injection pipe 77. The supply pipe 78 is provided outside the spirage chute 73. As shown in FIG. 6A, the supply pipe 78 is provided with a supply pipe valve 78a. The supply piping valve 78a is an on-off valve.

As shown in FIG. 4A, two flange joints 79 are provided: an injection pipe side flange joint 79a fixed to the injection pipe 77 and a supply pipe side flange joint 79b fixed to the supply pipe 78. There is.

The injection pipe side flange joint 79a is fixed to the end of the injection pipe 77 on the supply pipe 78 side. Further, as shown in FIG. 4B, the injection pipe side flange joint 79a is an annular member, and the injection pipe 77 is inserted therein. The injection pipe side flange joint 79a is formed with a plurality of through holes 99 (eight as an example in this embodiment). The plurality of through holes 99 are arranged at predetermined intervals in the circumferential direction.

The supply pipe side flange joint 79b is fixed to the end of the supply pipe 78 on the injection pipe 77 side. Since the shape of the supply pipe side flange joint 79b is the same as that of the injection pipe side flange joint 79a, detailed description thereof will be omitted. The supply pipe 78 is inserted inside the flange joint 79b on the supply pipe side.

The injection pipe side flange joint 79a and the supply pipe side flange joint 79b are arranged so that all the through holes communicate with each other, and are fastened and fixed by bolts (not shown) through which the through holes are inserted. Further, the injection pipe side flange joint 79a and the supply pipe side flange joint 79b are fastened and fixed so that the injection holes 77a formed in the injection pipe 77 face a predetermined direction. The injection formed in the injection pipe 77 is formed by removing each bolt, rotating the injection pipe side flange joint 79a and the injection pipe 77, and fixing the injection pipe side flange joint 79a and the supply pipe side flange joint 79b again with each bolt. The direction of the assist gas injected from the hole 77a can be changed. Therefore, the direction in which the assist gas is injected can be set to a desired angle.

As shown in FIG. 3, the spirage hopper 75 is a box-shaped member having a space inside. The spillage hopper 75 of the present embodiment is a so-called dry spillage hopper. A wet spillage hopper may be used.
A vent pipe 80 that reduces the pressure in the internal space communicates with the ceiling portion 75a of the spirage hopper 75. The vent valve 81 is provided in the vent pipe 80. By opening the vent valve 81, the internal space of the spirage hopper 75 and the external space of the spirage hopper 75 communicate with each other. As a result, the pressure inside the spirage hopper 75 can be reduced.

The vent valve 81 may be opened at the timing when the assist gas is injected from the assist gas injection unit 74. As a result, it is possible to suppress an increase in the internal pressure of the spirage hopper 75 at the timing of injecting the assist gas. Therefore, it is possible to suppress the backflow of the assist gas and the decrease in the injection pressure. Further, the pressure difference between the inside of the housing 11 and the inside of the spirage hopper 75 can be reduced, and the discharge of residual coal can be promoted.

The timing of opening the vent valve 81 may be at the same time as the injection of the assist gas, or may be after a predetermined time has elapsed from the timing of the injection of the assist gas. Further, it may be a predetermined time before the timing at which the assist gas is injected.

Next, the operation of the mill 10 according to the present embodiment will be described.

[Normal operation]
First, the operation of the mill 10 during normal operation will be described with reference to FIG. The normal operation means a state in which the fixed fuel is supplied from the fuel supply unit 17 to the rotary table 12 and the solid fuel is crushed on the rotary table 12.

When the solid fuel is supplied from the fuel supply unit 17 onto the rotary table 12, the roller 13 presses the solid fuel on the rotary table 12 to crush it. A part of the crushed solid fuel, which is the crushed solid fuel, is scattered from the top of the rotary table 12 to the outside in the radial direction by the centrifugal force of the rotary table 12. The scattered fuel after crushing is supplied from the primary air duct 27, and is dried and raised by the primary air passing through the outlet 25. The raised fuel after crushing is classified by the rotary classifier 16, and fuel having a particle size larger than a predetermined particle size is dropped as coarse-grained fuel and returned to the rotary table 12 for re-grinding. On the other hand, fuel having a particle size smaller than the predetermined particle size passes through the rotary classifier 16 as fine powder fuel, and is discharged from the outlet 19 to the outside of the housing 11 along with the air flow of the primary air. Foreign substances such as gravel and metal pieces mixed in the solid fuel, and those whose mass is too large to be conveyed by the primary air even after crushing, fall from the outer peripheral portion of the rotary table 12 to the bottom surface portion 11d of the housing 11. do. Residual coal and foreign matter (also referred to as “spillage” in the following description), which are crushed fuel that has fallen on the bottom surface 11d, are guided by the scraper 70 to the spillage chute 73 through the opening 11e and outside the housing 11. It is discharged to the spirage hopper 75.

[Emergency stop]
Next, the operation performed when the mill 10 according to the present embodiment is stopped in an emergency will be described. When the mill 10 detects an abnormality or the like, the mill 10 makes an emergency stop. When an emergency stop occurs, the supply of solid fuel from the fuel supply unit 17, the rotation of the rotary table 12, the introduction of the primary air from the primary air duct 27, and the like may be stopped. In such a case, the crushed fuel on the rotary table 12 remains on the rotary table 12. Further, a part of the crushed fuel that was being conveyed by the primary air falls and accumulates on the rotary table 12 or on the bottom surface portion 11d of the housing 11. At this time, since the rotation of the rotary table 12 is stopped, the rotation of the scraper 70 is also stopped. Therefore, the scraper 70 does not discharge the residual coal on the bottom surface 11d.

When the mill 10 is urgently stopped, an operation of lowering the oxygen concentration in the housing 11 (an operation of lowering the oxygen concentration) is performed. Specifically, by supplying nitrogen or steam as an inert gas into the housing 11 and lowering the oxygen concentration in the housing 11, the natural oxidation temperature rise and ignition of the residual coal remaining in the housing 11 are suppressed. ..

When it is determined that the oxygen concentration in the housing 11 is sufficiently lowered and the natural oxidation temperature rise and ignition of the residual coal are suppressed, the operation of discharging the residual coal in the housing 11 (clearing operation) is performed next. When the clearing operation is started, the rotary table 12 is first rotated. As a result, the scraper 70 also rotates. By rotating the rotary table 12, the residual coal on the rotary table 12 is scattered by the centrifugal force and falls to the bottom surface portion 11d of the housing 11. The residual coal deposited on the bottom surface 11d is guided by the scraper 70 to the opening 11e and flows into the spillage chute 73. The residual coal that has flowed into the spillage chute 73 circulates in the spillage chute 73 and is discharged to the spillage hopper 75 provided outside the housing 11. At this time, the assist gas may be injected by the assist gas injection unit 74 in the spirage chute 73.
In this way, the residual coal in the housing 11 is discharged, and the natural oxidation temperature rise and ignition of the residual coal are suppressed in the housing 11.

[Assist gas injection timing]
Next, the timing at which the assist gas injection unit 74 injects the assist gas will be described with reference to FIGS. 6A and 6B.
In the solid fuel crushing apparatus 100 of the present embodiment, the control unit 50 sets the injection amount of the assist gas injected from the assist gas injection unit 74 based on the load of the mill 10. Specifically, the control unit 50 of the present embodiment injects the assist gas during the clearing operation when the load becomes zero or during the low load (low coal supply amount) operation of the mill 10. This is based on the finding that the amount of residual coal deposited on the bottom surface 11d is maximized because the supply of primary air is stopped during the clearing operation. Further, it is based on the knowledge that during low load operation of the mill 10, the flow rate of the primary air is controlled to be small according to the decrease in the amount of coal supplied, so that the amount of spillage discharged increases.

Specifically, as shown in FIG. 6B, the control unit 50 supplies the mill 10 when the load (coal supply amount) of the mill 10 is equal to or more than the minimum (min) load value and is equal to or less than the predetermined value L1 load. The piping valve 78a is opened and a predetermined amount of assist gas is injected. When the load of the mill 10 is larger than the predetermined value L1 load, the supply pipe valve 78a is closed and the injection of the assist gas is stopped. The predetermined value L1 load is, for example, a value larger than the minimum (min) load and smaller than the 50% load.
When the clearing operation is started, the supply pipe valve 78a is opened and a predetermined amount of assist gas is injected.

The timing of injection of the assist gas is not limited to the above description. For example, as shown in FIG. 7B, the injection amount of the assist gas may be changed based on the load of the mill 10. In this case, as shown in FIG. 7A, the branch pipe 82 may be provided with respect to the supply pipe 78 so as to bypass the supply pipe valve 78a. The branch pipe 82 is arranged in parallel with the supply pipe 78. The branch pipe 82 is provided with a branch pipe valve 83 and an orifice 84. The branch piping valve 83 is an on-off valve.

In the example shown in FIG. 7B, when the load of the mill 10 is equal to or more than the minimum (min) load value and is equal to or less than the predetermined value L1 load, the control unit 50 opens the supply piping valve 78a. Inject a fixed amount of assist gas. Further, when the load of the mill 10 is larger than the predetermined value L1 load and is 100% or less, the control unit 50 closes the supply pipe valve 78a and opens the branch pipe valve 83. .. In this state, the assist gas is supplied to the ejection pipe via the branch pipe valve 83. The branch pipe valve 83 is provided with an orifice 84. Therefore, the amount of assist gas supplied to the ejection pipe is smaller in the case of supplying to the ejection pipe via the branch pipe valve 83 than in the case of supplying to the ejection pipe via the supply pipe 78. Become. Therefore, the injection amount of the assist gas is also reduced.
When the clearing operation is started, the branch pipe valve 83 is closed and the supply pipe valve 78a is opened to inject a predetermined amount of assist gas. As a result, the amount of assist gas used can be suppressed while suppressing the accumulation of residual coal due to the injection of assist gas.

Further, for example, as shown in FIG. 8B, the injection amount of the assist gas may be changed according to the load of the mill 10. In this case, as shown in FIG. 8A, the flow rate adjusting valve 85 is provided in the supply pipe 78 instead of the supply pipe valve 78a. The flow rate adjusting valve 85 can adjust the flow rate of the assist gas flowing inside the supply pipe 78 by adjusting the opening degree.

In the example shown in FIG. 8B, when the load of the mill 10 is equal to or greater than the minimum (min) load value and is equal to or less than the predetermined value L1 load, the control unit 50 substantially fully opens (adjusts) the flow rate adjusting valve 85. The rated flow rate opening of the valve), and a predetermined amount of assist gas is injected. Further, when the load of the mill 10 is larger than the predetermined value L1 load and is 100% or less, the control unit 50 adjusts the opening degree of the flow rate adjusting valve 85 according to the load. Specifically, as the load increases, the opening degree of the flow rate adjusting valve 85 is reduced to reduce the injection amount of the assist gas. Even when the load of the mill 10 is 100%, the injection amount of the assist gas is not set to zero, but a certain amount is injected.
When the clearing operation is started, the flow rate adjusting valve 85 is set to a substantially fully opened state (rated flow rate opening degree of the adjusting valve), and a predetermined amount of assist gas is injected. As a result, the amount of assist gas used can be suppressed while suppressing the accumulation of residual coal due to the injection of assist gas.

In this embodiment, the following effects are exhibited.
Most of the residual coal, which is the crushed fuel that has flowed into the spirage chute 73 through the opening 11e, falls into the region vertically below the opening 11e. In the present embodiment, the assist gas injection unit 74 (particularly, the injection pipe 77) is provided outside the opening 11e when the opening 11e is viewed from above. That is, the assist gas injection unit 74 is not provided in the region vertically below the opening 11e. As a result, the residual coal that has flowed into the spirage chute 73 through the opening 11e is unlikely to come into contact with or accumulate on the upper portion of the assist gas injection portion 74. Therefore, it is possible to make it difficult for the residual coal to be deposited on the assist gas injection unit 74. Thereby, the blockage of the spirage chute 73 can be suppressed.

Further, in the present embodiment, the spillage chute 73 extends from the connection portion of the spillage chute 73 with the opening 11e so as to be inclined with respect to the horizontal plane. As a result, a spirage that has a portion extending in the direction perpendicular to the horizontal plane (in other words, the vertical direction) at the connection portion with the opening 11e, and then connects to the portion and inclines with respect to the horizontal plane. The length (height) of the discharge device 60 in the vertical direction can be shortened as compared with the chute. As a result, the installation cost of the discharge device 60 can be reduced. Further, the discharge device 60 is arranged at the lower part of the mill 10. As a result, by reducing the height of the discharge device 60, the length (height) of the entire solid fuel crusher 100 in the vertical direction can be reduced, and the construction cost can be reduced. Further, the supporting steel frame of the solid fuel crushing device 100 may form a structure integrated with the supporting steel frame of the boiler 200. Therefore, the construction cost can be reduced by integrating the supporting steel frames of the solid fuel crushing device 100 and the boiler 200.

Further, the inlet opening 73a of the spirage chute 73 is formed so as to be larger than the opening 11e formed in the housing 11. As a result, the cross section of the flow path of the spirage chute 73 can be formed sufficiently large with respect to the amount of residual coal flowing into the spirage chute 73, so that the spillage chute 73 suppresses the blockage of the residual coal. can do.

Further, in the present embodiment, the scraper 70 that guides the residual coal to the opening 11e is rotating and moving. As a result, the residual coal guided by the scraper 70 moves outward in the radial direction due to centrifugal force when being guided. Therefore, the amount of residual coal flowing into the spirage chute 73 from the opening 11e is larger on the outer side than on the inner side in the radial direction (see the graph in FIG. 5). In the present embodiment, the assist gas injection unit 74 injects the assist gas toward the outside in the radial direction from the central axis C2 of the opening 11e. As a result, the assist gas can be injected into a region where the amount of residual coal flowing in is large and the gas is easily blocked. Therefore, the blockage of the spirage chute 73 can be more preferably suppressed.

In the present embodiment, the opening 11e is formed on the rotating track of the scraper 70. That is, the scraper 70 passes above the opening 11e. Therefore, the residual coal guided to the opening 11e by the scraper 70 starts to fall from the rear side (upstream side, in other words, the lower side of the paper surface of FIG. 4A) in the rotation direction R of the opening 11e. Therefore, the amount of residual coal flowing into the spirage chute 73 from the opening 11e is larger on the rear side than on the front side (downstream side, in other words, the upper side of the paper surface in FIG. 4A) in the rotation direction R. In the present embodiment, since the connection position of the supply pipe 78 that supplies the assist gas to the injection pipe 77 is the rear side (upstream side, in other words, the lower side of the paper surface of FIG. 4A) in the rotation direction R, the front side in the rotation direction R. The injection pressure of the injection hole 77a on the rear side in the rotation direction R is larger than that of the injection hole 77a on the side. As a result, the assist gas having a large injection pressure can be injected into a region where the amount of residual coal flowing in is large and the area is easily clogged. Therefore, the blockage of the spirage chute 73 can be more preferably suppressed.

[Modification 1]
Next, a modified example (modified example 1) of the present embodiment will be described with reference to FIG.
This modification is different from the first embodiment in that the connection flange portion 90 is provided. Since other points are the same as those of the first embodiment, the same reference numerals are given to the same configurations, and detailed description thereof will be omitted.
As described above, the connection flange portion 90 is provided between the flange portion 73c of the spirage chute 73 and the bottom surface portion 11d of the housing 11. The connection flange portion 90 is a quadrangular frame-shaped member having an opening 90a formed in the central region. The opening 90a formed in the connection flange portion 90 has substantially the same shape and size as the opening 11e formed in the bottom surface portion 11d of the housing 11. The connection flange portion 90 is arranged so that the inner edge of the frame of the opening 90a formed in the connection flange portion 90 and the inner edge of the opening 11e formed in the bottom surface portion 11d are substantially continuous. The upper surface of the connection flange portion 90 may be connected to the lower surface of the bottom surface portion 11d in surface contact, or a partial area or the entire area is connected between the upper surface of the connection flange portion 90 and the lower surface of the bottom surface portion 11d. May be connected to the flange via a sealing member. A plurality of through holes penetrating in the vertical direction are formed in the connection flange portion 90, and the size of the through holes on the lower surface side of the connection flange portion 90 is a stepped hole formed to be large. The connection flange portion 90 and the housing 11 are formed by a first bolt 91 through which a through hole formed in the connection flange portion 90 is inserted and screwed into a bolt hole (female thread portion) formed in the bottom surface portion 11d of the housing 11. It is fixed. At this time, the bolt head portion of the first bolt 91 is housed in the stepped hole portion having a large through hole on the lower surface side of the connection flange portion 90, so that the bolt head portion is housed with the flange portion 73c of the spirage chute 73. It may not interfere with the connection.
Further, the lower surface of the connecting flange portion 90 is connected in surface contact with the upper surface of the flange portion 73c, or is connected via a sealing member. The connection flange portion 90 is formed with a plurality of bolt holes (female threaded portions) on the outside of the through holes. Each bolt hole communicates with a through hole formed in the flange portion 73c. The connection flange portion 90 and the flange portion 73c are fixed by a second bolt 92 through which a through hole formed in the flange portion 73c is inserted and screwed into the bolt hole.

By providing the connection flange portion 90 in this way, the spirage chute 73 having an inlet opening 73a larger than the opening 11e can be installed and fixed to the existing mill 10. That is, by providing the connection flange portion 90, the spillage chute 73 can be fixed to the housing 11 by utilizing the existing bolt holes formed on the lower surface of the bottom surface portion 11d. This makes it possible to easily replace the existing mill 10 with a spirage chute 73 having an inlet opening 73a larger than the opening 11e.
In this modification as well, the injection pipe 77 of the assist gas injection unit 74 is not provided in the region vertically below the opening 11e, and the residual coal that has flowed into the spirage chute 73 through the opening 11e is the assist gas injection unit. It is difficult to contact or deposit on the upper part of 74. Thereby, the blockage of the spirage chute 73 can be suppressed.

[Modification 2]
Next, a modified example (modified example 2) of the present embodiment will be described with reference to FIG.
This modification is mainly different from the first embodiment in that the spirage chute 73A has a vertical portion 93 and a recess 95. Since other points are the same as those of the first embodiment, the same reference numerals are given to the same configurations, and detailed description thereof will be omitted.

The spirage chute 73A according to this modification has a portion that extends in the vertical direction with respect to the horizontal plane at the connection portion with the opening 11e, and has a vertical portion 93 communicating with the opening 11e and a lower end of the vertical portion 93. It has an inclined portion 94 which is bent from the surface and extends obliquely downward so as to be inclined with respect to the horizontal plane. An inlet opening 93a is formed at the upstream end of the vertical portion 93. The shape of the entrance opening 93a is substantially the same as that of the opening 11e. The vertical portion 93 is arranged so that the inner edge of the entrance opening 93a and the inner edge of the opening 11e are substantially continuous. A flange portion 73c is provided on the outer peripheral surface of the vertical portion 93, and the spirage chute 73A is fixed to the bottom surface portion 11d of the housing 11 by a bolt 73e penetrating the flange portion 73c.

A recess 95 protruding toward the central axis C1 of the housing 11 is formed at the upper end of the bottom surface of the inclined portion 94 connected to the lower end of the vertical portion 93. That is, the recess 95 is provided so as to form a space overhanging the outside of the opening 11e when the opening 11e is viewed in a plan view. The recess 95 accommodates the injection pipe 77 of the assist gas injection section 74. The bottom surface 95a of the recess 95 is inclined so that the inclined portion 94 side is located downward. As a result, it is possible to prevent residual coal from accumulating on the bottom surface 95a of the recess 95. That is, it is possible to prevent residual coal from accumulating inside the recess 95.

Also in this modification, the injection pipe 77 of the assist gas injection unit 74 is provided outside the opening 11e when the opening 11e is viewed in a plan view. It is possible to make it difficult for the residual coal that has flowed into the spirage chute 73A through the opening 11e to be deposited on the assist gas injection unit 74. Thereby, the blockage of the spirage chute 73A can be suppressed.

[Modification 3]
Next, a modified example (modified example 3) of the present embodiment will be described with reference to FIG.
This modification is different from the first embodiment in that the spirage chute 73A has a vertical portion 93 and a recess 96. Further, it is different from the first embodiment in that an assist gas duct 97 is provided instead of the assist gas injection unit 74. Since other points are the same as those of the first embodiment, the same reference numerals are given to the same configurations, and detailed description thereof will be omitted.

The spillage chute 73B according to this modification has a portion that extends in the vertical direction with respect to the horizontal plane at the connection portion with the opening 11e, and has a vertical portion 93 communicating with the opening 11e and a lower end of the vertical portion 93. It has an inclined portion 94 which is bent from the surface and extends obliquely downward so as to be inclined with respect to the horizontal plane. Since the configurations of the vertical portion 93 and the inclined portion 94 are the same as those of the vertical portion 93 and the inclined portion 94 according to the above-described second modification, the same reference numerals are given and detailed description thereof will be omitted.
At the connection position between the lower end side of the vertical portion 93 and the bottom surface of the upper end side of the inclined portion 94, a recess 96 of a space protruding toward the central axis C1 side of the housing 11 is formed. The recess 96 is provided so as to form a space overhanging the outside of the opening 11e when the opening 11e is viewed in a plan view. The assist gas duct 97 is housed in the recess 96. The assist gas duct 97 and the internal space of the spirage chute 73B are separated by a partition wall 98. A communication hole 98a is formed in the partition wall portion 98. The communication hole 98a communicates the assist gas duct 97 with the internal space of the spirage chute 73B. Assist gas is introduced and circulated in the assist gas duct 97, and the assist gas in the assist gas duct 97 is injected into the internal space of the spirage chute 73B through the communication hole 98a. That is, in this modification, the assist gas duct 97 has the same assist gas ejection function as the injection pipe 77 of the first embodiment.

In this modification, the assist gas duct 97 is provided outside the opening 11e when the opening 11e is viewed in a plan view. As a result, it is possible to make it difficult for the residual coal that has flowed into the spirage chute 73B through the opening 11e to be deposited on the assist gas duct 97. Thereby, the blockage of the spirage chute 73B can be suppressed.

The present disclosure is not limited to the above embodiment, and can be appropriately modified as long as it does not deviate from the gist thereof.
For example, in the above embodiment, an example in which the inclination angle of the spirage chute 73 is set to the rest angle or more has been described, but the present disclosure is not limited to this. The assist gas ejection from the assist gas injection unit 74 may be such that the inclination angle of the spirage chute is equal to or less than the rest angle. By setting the inclination angle of the spirage chute to be equal to or less than the rest angle, the length (height) of the spirage chute in the vertical direction can be shortened as compared with the case where the angle of inclination is equal to or greater than the rest angle. Further, in the above embodiment, by providing the assist gas injection unit 74 in the spillage chute 73, it is possible to suppress the blockage of the spillage chute even if the inclination angle of the spillage chute is set to the rest angle or less. As a result, the overall height of the solid fuel crusher 100 can be made lower, so that the construction cost of the solid fuel crusher 100 and the boiler 200 can be further reduced.

Further, in the above embodiment, an example in which the shape of the opening 11e formed in the bottom surface portion 11d of the housing 11 is rectangular in a plan view has been described, but the present disclosure is not limited to this. For example, the shape of the opening formed in the bottom surface portion 11d of the housing 11 may be a polygonal shape other than a quadrangle in a plan view, or may be a circular shape in a plan view.

Further, a part of the supply pipe 78 that supplies the assist gas to the injection pipe 77 may be formed of a flexible member (for example, a flexible hose). With this configuration, the supply pipe can be deformed, so that restrictions on the layout of the supply pipe can be suppressed. Therefore, the installation space of the supply pipe can be saved. Further, the flexible member attenuates the vibration transmitted from the mill 10. Therefore, the transmission of vibration to the injection pipe 77 can be suppressed.

Further, in the above embodiment, the injection pressure of the injection hole 77a arranged on the rear side in the rotation direction R of the scraper 70 is larger than that of the injection hole 77a arranged on the front side in the rotation direction R. As described, the present disclosure is not limited to this. For example, the injection amount of the assist gas may be larger in the region on the rear side in the rotation direction R of the scraper 70 than in the region on the front side in the rotation direction R. Examples of the method of increasing the injection amount include a method of increasing the diameter of the injection holes 77a arranged in the rear region in the rotation direction R, and a method of increasing the diameter of the plurality of injection holes 77a arranged in the rear region in the rotation direction R. There is a method of shortening the interval. With such a configuration, the injection amount of the assist gas can be increased in the region on the rear side in the rotation direction R where the residual coal discharge amount is large, so that the residual coal can be preferably discharged.

Further, in the above embodiment, an example in which the control unit 50 adjusts the amount of assist gas injected from the assist gas injection unit 74 and the injection timing based on the load of the mill 10 has been described. Not limited to. For example, the control unit 50 detects the pressure difference between the pressure in the space below the rotary table 12 and the pressure inside the spillage hopper 75, and detects the blockage of the spillage chute 73 by monitoring the pressure difference. You may. When the spillage chute 73 is blocked, the differential pressure becomes large. Therefore, when the differential pressure becomes larger than a predetermined value, it may be determined that the blockage has occurred.
Further, when the control unit 50 determines that the blockage has occurred, the amount of the assist gas injected from the assist gas injection unit 74 is set to be larger than the injection amount set according to the coal supply amount (mill load). The blockage may be eliminated by temporarily increasing the amount and injecting the gas. Further, it may be set to return to the injection amount of the assist gas according to the coal supply amount (mill load) when the differential pressure returns to the original value after the blockage is cleared.

The operation method of the discharge device, the solid fuel crusher, the boiler system, and the discharge device described in each of the above-described embodiments is grasped as follows, for example.

The discharge device according to one aspect of the present disclosure discharges the crushed solid fuel from an opening (11e) provided in a housing (11) forming an outer shell of a crusher (10) that crushes the solid fuel. A duct (73) of the device (60), which is provided below the opening (11e), communicates with the opening (11e), and allows the crushed solid fuel discharged from the opening (11e) to flow. And an injection unit (74) provided inside the duct (73) to inject a fluid into the inside of the duct (73), and the injection unit (74) is below the opening (11e). The opening (11e) is provided outside the opening (11e) when viewed in a plan view.

Most of the crushed solid fuel that has flowed into the duct through the opening falls into the region vertically below the opening. In the above configuration, the injection portion is provided on the outside of the opening when the opening is viewed from above. That is, the injection portion is not provided in the region vertically below the opening. As a result, the crushed solid fuel that has flowed into the duct through the opening is unlikely to come into contact with the upper part of the injection portion. Therefore, it is possible to make it difficult for the crushed solid fuel to be deposited on the injection portion. As a result, clogging of the crushed solid fuel can be suppressed in the duct.

Further, in the discharge device according to one aspect of the present disclosure, the duct (73) has an inlet opening (73a) communicating with the opening (11e) and is inclined with respect to a horizontal plane from the inlet opening (73a). The entrance opening (73a) is formed to have a size larger than that of the opening (11e).

In the above configuration, the duct extends from the inlet opening so as to be inclined with respect to the horizontal plane. That is, the duct is inclined with respect to the horizontal plane at the portion communicating with the opening. As a result, the length (height) of the discharge device in the vertical direction can be shortened as compared with the duct extending in the direction perpendicular to the horizontal plane (in other words, the vertical direction) from the inlet opening. As a result, the installation cost of the discharge device can be reduced. In particular, for example, when the discharge device is arranged below the crusher, the length (height) of the entire crusher in the vertical direction can be reduced, so that the construction cost of the crusher and the boiler can be reduced. Can be done.
Further, the entrance opening of the duct is formed larger than the opening formed in the housing. As a result, the injection portion can be prevented from being easily provided in the region vertically below the opening formed in the housing, so that the crushed solid fuel is less likely to be deposited on the injection portion, and the injection portion is at the entrance of the duct. The fluid can be ejected to the solid fuel which is effectively crushed by being provided near the opening. As a result, the fluid can be effectively ejected into the crushed solid fuel while forming the flow path cross section of the duct sufficiently large with respect to the amount of the crushed solid fuel flowing into the duct. Blockage of crushed solid fuel in the duct can be suppressed.

The solid fuel crusher according to one aspect of the present disclosure includes the discharge device (60) according to any one of the above and the crusher (10) for crushing the solid fuel, and the crusher (10) includes the crusher (10). ,
It has a rotary table (12) housed inside the housing (11) and rotates about a central axis (C1) extending in the vertical direction, and pulverizes the solid fuel on the rotary table (12). The housing is provided below the rotary table (12) and the portion (12, 13), and the upper surface of the bottom surface portion (11d) of the housing (11) is rotationally moved around the central axis (C1). The opening (11e) has a sweeping portion (70) for guiding the crushed solid fuel deposited on the bottom surface to the opening (11e) formed in (11), and the opening (11e) is the central axis (11e). It is formed on the orbit of the sweeping portion (70) that rotates and moves on the outer side in the radial direction of C1).

Further, in the solid fuel crushing apparatus according to one aspect of the present disclosure, the injection unit (74) injects a fluid from the center of the opening (11e) toward the outside in the radial direction.

In the above configuration, the sweeping portion that guides the crushed solid fuel accumulated on the bottom surface of the housing to the opening is rotationally moved. As a result, the crushed solid fuel guided by the sweeping portion moves outward in the radial direction by centrifugal force while being guided. Therefore, the amount of crushed solid fuel flowing into the duct from the opening is larger on the outside than on the inside in the radial direction. In the above configuration, the injection unit injects the fluid outward in the radial direction from the center of the opening. As a result, the amount of crushed solid fuel that flows in is large, and the fluid can be injected toward a region that is easily blocked. Therefore, the blockage of the duct can be suppressed more preferably.

Further, in the solid fuel crushing apparatus according to one aspect of the present disclosure, the injection unit (74) has a plurality of injection holes (77a) for injecting a fluid, and the plurality of injection holes (77a) are swept. The protrusions (70) are arranged side by side along the rotation direction (R) in which the sweeping portion (70) rotates, and the sweep portion (70) is located on the rear side in the rotation direction rather than the front side in the rotation direction (R). The injection pressure for injecting the fluid is larger.

In the above configuration, an opening is formed in the orbit of the sweep portion. That is, the sweeping portion passes above the opening. Therefore, in the crushed solid fuel guided to the opening by the sweeping portion, the crushed solid fuel starts to fall from the rear side (upstream side) of the opening in the rotational direction. Therefore, the amount of crushed solid fuel flowing into the duct from the opening is larger on the rear side than on the front side (downstream side) in the rotational direction. In the above configuration, the injection pressure of the fluid is larger in the injection hole on the rear side in the rotation direction than in the injection hole on the front side in the rotation direction. As a result, it is possible to inject a fluid having a large injection pressure into a region where a large amount of crushed solid fuel flows in and is likely to be blocked. Therefore, the blockage of the duct can be suppressed more preferably.

The boiler system according to one aspect of the present disclosure burns the solid fuel crusher (100) according to any one of the above and the solid fuel crushed by the solid fuel crusher (100) to generate steam. It is equipped with a boiler (200).

The method of operating the discharge device according to one aspect of the present disclosure is to discharge the crushed solid fuel from an opening (11e) provided in a housing forming an outer shell of a crusher (10) that crushes the solid fuel. A method of operating the device (60), wherein the discharge device (60) is provided below the opening (11e), communicates with the opening (11e), and is pulverized to be discharged from the opening (11e). A duct (73) through which the solid fuel flows, and a duct (73) provided inside the duct (73) and outside the opening (11e) when the opening (11e) is viewed in a plan view. It has an injection unit (74) for injecting a fluid inside the injection unit (74), and includes an injection step for injecting a fluid from the injection unit (74).

1: Boiler system 10: Mill (crusher)
11: Housing
11a: Inner peripheral surface 11b: Side surface 11d: Bottom surface 11e: Opening 12: Rotating table 13: Roller 14: Drive 16: Rotary classifier 16a: Blade 17: Fuel supply 18: Motor 19: Outlet 20: Supply Charcoal machine 21: Bunker 22: Conveying part 23: Motor 24: Down spout part 25: Outlet 26: Vane 27: Primary air duct 30: Blower part 30a: Hot gas flow path 30b: Cold gas flow path 30c: Hot gas damper 30d : Cold gas damper 31: Primary air ventilator 32: Push-in air ventilator 34: Heat exchanger 40: State detection unit 41: Bottom part 42: Ceiling part 45: Journal head 47: Support arm 48: Support shaft 49: Pressing device 50 : Control unit 60: Discharge device 70: Scraper (sweep unit)
71: Arm part 72: Moving part 73: Spirage chute 73A: Spirage chute 73B: Spirage chute 73a: Inlet opening 73b: Outlet opening 73c: Flange part 73d: Bottom surface 73e: Bolt 74: Assist gas injection part (injection part) )
75: Spirage hopper 75a: Ceiling part 76: Gate valve 77: Injection pipe 77a: Injection hole 78: Supply pipe 78a: Supply pipe valve 79: Flange joint 79a: Injection pipe side flange joint 79b: Supply pipe side flange joint 80: Vent piping 81: Vent valve 82: Branch piping 83: Branch piping valve 84: orifice 85: Flow control valve 90: Connection flange portion 90a: Opening 91: First bolt 92: Second bolt 93: Vertical portion 94: Inclined portion 95 : Recessed 95a: Bottom surface 96: Recessed 97: Assist gas duct 98: Partition 98a: Communication hole 100: Solid fuel crusher 100a: Primary air flow path 100b: Supply flow path 200: Boiler 210: Fire furnace 220: Burner part

Claims (7)

A discharge device that discharges the crushed solid fuel from an opening provided in a housing that forms the outer shell of a crusher that crushes the solid fuel.
A duct provided below the opening, communicating with the opening, and allowing the crushed solid fuel discharged from the opening to flow through.
An injection unit provided inside the duct and injecting a fluid into the duct is provided.
The injection unit is a discharge device that is below the opening and is provided outside the opening when the opening is viewed in a plan view. The duct has an inlet opening that communicates with the opening and extends from the inlet opening so as to be inclined with respect to the horizontal plane.
The discharge device according to claim 1, wherein the entrance opening is formed in a size larger than the opening. The discharge device according to claim 1 or 2,
The crusher for crushing the solid fuel is provided.
The crusher
A crushing unit that is housed inside the housing and has a rotary table that rotates about a central axis extending in the vertical direction, and crushes the solid fuel on the rotary table.
The crushed solid fuel deposited on the bottom surface is guided to an opening formed in the housing by rotating and moving the upper surface of the bottom surface of the housing around the central axis, which is provided below the rotary table. With a sweeping part,
The opening is a solid fuel crushing device formed on the orbit of the sweeping portion that rotates and moves outside in the radial direction of the central axis. The solid fuel crushing apparatus according to claim 3, wherein the injection unit injects a fluid toward the outside in the radial direction from the center of the opening. The injection unit has a plurality of injection holes for injecting a fluid.
The plurality of injection holes are arranged side by side along the rotation direction in which the sweep portion rotates, and the rear side of the sweep portion in the rotation direction is arranged more than the front side of the sweep portion in the rotation direction. The solid fuel pulverizer according to claim 3 or 4, wherein the injection pressure for injecting a fluid is large. The solid fuel crusher according to any one of claims 3 to 5.
A boiler that burns the solid fuel crushed by the solid fuel crusher to generate steam, and
Boiler system with. A method of operating a discharge device that discharges the crushed solid fuel from an opening provided in a housing that forms the outer shell of a crusher that crushes the solid fuel.
The discharge device is
A duct provided below the opening, communicating with the opening, and allowing the crushed solid fuel discharged from the opening to flow through.
It has an injection portion inside the duct, which is provided outside the opening when the opening is viewed in a plan view, and which injects a fluid into the inside of the duct.
A method of operating a discharge device including an injection step for injecting a fluid from the injection unit.

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