Spillage hopper and pulverizer, and operation method of spillage hopper

Abstract

To provide a spillage hopper improving amount of a stored object that can be stored in the spillage hopper.SOLUTION: A spillage hopper comprises: a body part 66 which stores exhaust materials discharged from a pulverizer 10; an exhaust port 72b which is formed at a side wall part 72 of the body part 66; and a coating part 90 arranged in the body part 66 which covers the exhaust port 72b and forms space therein. The exhaust port 72b is opened to the space and controls upper limit amount of a stored object stored in the body part 66. The coating part 90 includes: a side wall part 90a regulating a lateral side of the space; a bottom face part 90c blocking a lower side of the space; and a communication port arranged at an upper side relative to the exhaust port 72b which communicates between the space and outside of the coating part 90.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a spillage hopper and grinder and a method of operating a spillage hopper. [Background technology]

[0002] Conventionally, in thermal power plants, solid fuels (carbon-containing solid fuels) such as coal and biomass fuels are pulverized into fine powder within a predetermined particle size range using, for example, a vertical mill (pulverizer) and then supplied to a combustion device. The mill crushes the solid fuel, such as coal or biomass fuel, fed onto a rotary table by crushing it between the rotary table and a crushing roller. A carrier gas is supplied from the outer periphery of the rotary table, and the pulverized fuel is sorted into fine particles within a predetermined particle size range using a classifier. The fine particles are then transported to a boiler and combusted in a combustion device. In thermal power plants, steam is generated by heat exchange with combustion gas produced by combustion in the boiler. This steam drives a steam turbine, which in turn drives a generator connected to the steam turbine, thereby generating electricity.

[0003] Such mills are equipped with discharge devices called pyrite dischargers, spillage hoppers, etc., for discharging and storing foreign matter (pyrite, spillage) such as stones and metal fragments mixed in with the solid fuel that has been fed in (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-151361 Summary of the Invention [Problem to be solved by the invention]

[0005] When a pulverizer is shut down, the pulverized solid fuel (e.g., coal, also called residual charcoal) remaining inside the pulverizer must be discharged to the outside to prevent ignition of the solid fuel remaining inside the pulverizer during the shutdown period or when the pulverizer is restarted. During normal shutdown, a purge operation is performed for a certain period of time after the fuel supply to the pulverizer is stopped, by continuing to supply a carrier gas to rotate the pulverizer's grinding table and discharging the solid fuel remaining inside the pulverizer (particularly on the grinding table) to the combustion device. On the other hand, when the pulverizer is shut down due to a malfunction in the combustion device, a clearing operation is performed to discharge the residual charcoal from the pulverizer to the outside. In the clearing operation, the pulverizer table is rotated without supplying a carrier gas, causing the residual charcoal on the grinding table to fall to the bottom plate (bottom portion) of the pulverizer by centrifugal force. A scraper that rotates on the bottom portion of the pulverizer guides the solid fuel and other materials that have fallen and accumulated on the bottom portion to an opening formed in the bottom portion, from which they are discharged to a spillage hopper via a spillage chute.

[0006] During clearing operation, if a large amount of residual coal flows into the spillage hopper, there is a possibility that the residual coal cannot be stored in the spillage hopper.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a spillage hopper and crusher that can increase the amount of material that can be stored, as well as a method for operating a spillage hopper. [Means for solving the problem]

[0008] In order to solve the above problems, the spillage hopper, crusher, and method of operating the spillage hopper of the present disclosure employ the following means. A spillage hopper according to one aspect of the present disclosure comprises a main body portion that stores waste material discharged from a crusher therein, a discharge outlet formed in a side wall portion of the main body portion, and a covering portion that covers the discharge outlet inside the main body portion and forms a space inside, the discharge outlet opening into the space and controlling the upper limit amount of waste material stored inside the main body portion, the covering portion having side wall portions that define the sides of the space and a bottom portion that closes the lower side of the space, and a communication port that connects the space with the space outside the covering portion is formed above the discharge outlet.

[0009] Furthermore, a method of operating a spillage hopper according to one aspect of the present disclosure is a method of operating a spillage hopper, the spillage hopper comprising a main body portion that stores discharged material from a crusher inside, a discharge outlet formed in a side wall portion of the main body portion, and a covering portion that covers the discharge outlet inside the main body portion and forms a space inside, the discharge outlet opening into the space and managing the upper limit amount of material stored inside the main body portion, the covering portion having side wall portions that define the sides of the space and a bottom portion that closes the lower side of the space, and a communication port that connects the space with the space outside the covering portion is formed above the discharge outlet. [Effects of the Invention]

[0010] According to the present disclosure, the amount of material that can be stored in the spillage hopper can be increased. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a power generation plant equipped with a spillage hopper according to the present disclosure. [Figure 2] FIG. 1 is a front view of a spillage hopper of the present disclosure. [Figure 3] FIG. 1 is a side view of a spillage hopper of the present disclosure. [Figure 4] FIG. 2 is a perspective view of a housing and cover of the present disclosure. [Figure 5] FIG. 2 is a perspective view of a housing and cover of the present disclosure. [Figure 6] FIG. 2 is a perspective view showing a cover of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of a spillage hopper, a crusher, and a method of operating a spillage hopper according to the present disclosure will be described with reference to the drawings. As shown in FIG. 1, the power plant 1 includes a solid fuel pulverizer 100 and a boiler 200.

[0013] In the following explanation, "upper" refers to the vertically upward direction, and "upper" in terms such as upper part and upper surface refers to the vertically upward part. Similarly, "lower" refers to the vertically downward part, and the vertical direction is not precise and may include errors.

[0014] The solid fuel pulverizer 100 is a device that pulverizes solid fuel (carbon-containing solid fuel) such as coal or biomass fuel, generates pulverized fuel, and supplies it to a burner (combustion device) 220 of a boiler 200. The power plant 1 including the solid fuel pulverizer 100 and the boiler 200 shown in FIG. 1 is equipped with one solid fuel pulverizer 100, but it may also be a system equipped with multiple solid fuel pulverizers 100 corresponding to each of the multiple burners 220 of one boiler 200.

[0015] The solid fuel pulverizer 100 comprises a vertical mill (pulverizer) 10, a coal feeder (fuel supplier) 20, a blower (carrier gas supplier) 30, a state detection unit 40, a control unit (determination unit) 50, and an exhaust device 60.

[0016] The mill 10, which pulverizes solid fuel such as coal or biomass fuel to be supplied to the boiler 200 into finely divided fuel, which is a finely divided solid fuel, may be of a type that pulverizes only coal, or may be of a type that pulverizes only biomass fuel, or may be of a type that pulverizes biomass fuel together with coal.

[0017] Here, biomass fuel refers to organic resources derived from renewable living organisms, such as thinned wood, waste wood, driftwood, grass, waste, sludge, tires, and recycled fuels (pellets and chips) made from these materials, but is not limited to the ones listed here.Biomass fuels are carbon neutral, meaning they do not emit carbon dioxide, a greenhouse gas, because they absorb carbon dioxide during the biomass growth process, and various uses for them are being considered.

[0018] The mill 10 comprises a housing 11, a grinding table (rotary table) 12, grinding rollers 13, a drive unit 14, a mill motor 15 connected to the drive unit 14 and driving the grinding table 12 to rotate, a rotary classifier 16, a fuel supply unit 17, a classifier motor 18 that drives the rotary classifier 16 to rotate, and a scraper (not shown) that removes deposits accumulated on the bottom surface 41 of the housing 11.

[0019] The housing 11 is formed in a cylindrical shape extending in the vertical direction, and is a case that accommodates the crushing table 12, the crushing rollers 13, the rotary classifier 16, and the fuel supply unit 17. A fuel supply unit 17 is attached to the center of the ceiling 42 of the housing 11. This fuel supply unit 17 supplies solid fuel introduced from the bunker 21 into the housing 11, and is disposed vertically at the center of the housing 11, with its lower end extending into the interior of the housing 11. The shape of the housing 11 may be changed as appropriate depending on the shapes of the components to be housed. For example, if the outer shape of the rotary classifier 16 is large, the diameter of the housing 11 may be increased only around that periphery.

[0020] A drive unit 14 is installed near the bottom surface 41 of the housing 11, and a mill motor 15 connected to the drive unit 14 transmits a driving force to rotate the grinding table 12, which is rotatably arranged. The grinding table 12 is a circular member in a plan view, and is disposed so that the lower end of the fuel supply unit 17 faces it. The upper surface of the grinding table 12 may, for example, be inclined so that the center is low and increases toward the outside, with the outer periphery curved upward. Alternatively, a convex portion may be provided in the center, so that the center and outer periphery are higher. The fuel supply unit 17 supplies solid fuel (for example, coal or biomass fuel in this embodiment) from above toward the crushing table 12 below, and the crushing table 12 crushes the supplied solid fuel between itself and the crushing rollers 13.

[0021] When solid fuel is fed from the fuel supply unit 17 toward the approximate center region of the grinding table 12, the centrifugal force generated by the rotation of the grinding table 12 guides the solid fuel toward the outer periphery of the grinding table 12, where it is pinched and ground between the grinding table 12 and the grinding roller 13. The ground solid fuel is blown upward by the carrier gas (hereinafter referred to as "primary air") guided from the carrier gas flow path (hereinafter referred to as "primary air flow path") 100a, and is guided to the rotary classifier 16.

[0022] An outlet (not shown) is provided on the outer periphery of the grinding table 12, through which primary air flowing in from the primary air flow path 100a flows out into the space above the grinding table 12 within the housing 11. A swirl vane (not shown) is provided at the outlet, which imparts a swirling force to the primary air blown out from the outlet. The primary air imparted with the swirling force by the swirl vane becomes an airflow having a swirling velocity component, and transports the solid fuel pulverized on the grinding table 12 to the rotary classifier 16 located above within the housing 11. The swirl vane may be provided on the grinding table 12 so as to rotate together with the grinding table 12, or may be fixedly provided on the housing 11 side. Of the pulverized solid fuel, particles larger than a predetermined particle size are classified by the rotary classifier 16, or fall without reaching the rotary classifier 16 and are returned to the grinding table 12, where they are pulverized again between the grinding table 12 and the grinding roller 13.

[0023] The crushing roller 13 is a rotating body that crushes the solid fuel supplied onto the crushing table 12 from the fuel supply unit 17. The crushing roller 13 is pressed against the upper surface of the crushing table 12 and cooperates with the crushing table 12 to crush the solid fuel.

[0024] 1 shows only one representative crushing roller 13, but multiple crushing rollers 13 are arranged at regular intervals in the circumferential direction so as to press against the upper surface of the crushing table 12. For example, three crushing rollers 13 are arranged at equal intervals in the circumferential direction on the outer periphery, at angular intervals of 120°. In this case, the portions of the three crushing rollers 13 that come into contact with the upper surface of the crushing table 12 (pressing portions) are equidistant from the rotational axis of the crushing table 12.

[0025] The crushing roller 13 can swing up and down, for example, by a journal head 45, and is supported so as to be able to move toward and away from the upper surface of the crushing table 12. When the crushing table 12 rotates, the crushing roller 13 receives a rotational force from the crushing table 12 and rotates with it, with the outer circumferential surface of the crushing roller 13 in contact with the solid fuel on the upper surface of the crushing table 12. When solid fuel is supplied from the fuel supply unit 17, the solid fuel is pressed between the crushing roller 13 and the crushing table 12 and crushed.

[0026] A support arm 47 of the journal head 45 is supported on the side of the housing 11 by a support shaft 48 whose middle section is aligned horizontally, allowing the crushing roller 13 to swing up and down around the support shaft 48. A pressing device 49 is provided at the upper end section vertically above the support arm 47. The pressing device 49 is fixed to the housing 11 and applies a load to the crushing roller 13 via the support arm 47 etc. so as to press the crushing roller 13 against the crushing table 12.

[0027] The drive unit 14 is a device that transmits a drive force to the grinding table 12 and rotates the grinding table 12 around its central axis. The drive unit 14 is connected to a mill motor 15 and transmits the drive force of the mill motor 15 to the grinding table 12.

[0028] The rotary classifier 16 is provided at the top of the housing 11 and has a hollow, approximately inverted cone or cylindrical outer shape. The rotary classifier 16 is provided with a plurality of blades 16a extending in the vertical direction around its outer periphery. The blades 16a are provided at predetermined intervals (equally spaced) around the central axis of the rotary classifier 16.

[0029] The rotary classifier 16 is a device that classifies solid fuel pulverized by the pulverizing table 12 and pulverizing rollers 13 (hereinafter, the pulverized solid fuel will be referred to as "pulverized fuel") into particles larger than a predetermined particle size (for example, 70 to 100 μm for coal) (hereinafter, pulverized fuel exceeding the predetermined particle size will be referred to as "coarse pulverized fuel") and particles smaller than the predetermined particle size (hereinafter, pulverized fuel smaller than the predetermined particle size will be referred to as "fine pulverized fuel"). The rotary classifier 16, which classifies by rotation, is also called a rotary separator, and is given a rotational driving force by a classifier motor 18 controlled by a control unit 50, and rotates around a fuel supply unit 17 centered on a cylindrical axis (not shown) extending in the vertical direction of the housing 11. The classifier may be a fixed classifier having a fixed hollow inverted cone-shaped casing and a plurality of fixed swirl vanes on the outer periphery of the casing instead of the blades 16a.

[0030] When the pulverized fuel reaches the rotary classifier 16, due to the relative balance between the centrifugal force generated by the rotation of the blades 16a and the centripetal force of the primary air flow, large diameter coarse pulverized fuel particles are knocked down by the blades 16a and returned to the pulverizing table 12 to be pulverized again, and the pulverized fuel is led to the outlet port 19 in the ceiling 42 of the housing 11. The pulverized fuel classified by the rotary classifier 16 is discharged from the outlet port 19 together with the primary air into the pulverized fuel supply passage 100b and supplied to the burner 220 of the boiler 200. When the solid fuel is coal, the pulverized fuel supply passage 100b is also called a pulverized coal pipe.

[0031] A scraper (not shown) is disposed below the grinding table 12. The scraper is fixed to the grinding table 12 and rotates as the grinding table 12 rotates. The scraper has a sliding part that slides on the upper surface of the bottom part 41 of the housing 11. An opening is formed in the bottom part 41 on the rotational path of the sliding part. The scraper guides pulverized fuel and foreign matter accumulated on the bottom part 41 to the opening. The pulverized fuel and foreign matter guided to the opening are discharged to the outside of the mill 10 by the discharge device 60.

[0032] The fuel supply unit 17 is attached so that its lower end extends vertically into the interior of the housing 11 so as to penetrate the ceiling 42 of the housing 11, and supplies solid fuel fed from the top of the fuel supply unit 17 to the approximate center region of the grinding table 12. The fuel supply unit 17 is supplied with solid fuel from the coal feeder 20. A rotary valve may be provided at a midpoint of the fuel supply unit 17.

[0033] The coal feeder 20 includes a conveying unit 22 and a coal feeder motor 23. The conveying unit 22 is, for example, a belt conveyor, and by the driving force provided by the coal feeder motor 23, conveys the solid fuel discharged from the lower end of the downspout 24 located directly below the bunker 21 to the top of the fuel supply unit 17 of the mill 10 and inputs it into the fuel supply unit 17. Normally, primary air is supplied to the inside of the mill 10 to transport pulverized fuel to the burner 220, and the pressure therein is higher than that of the coal feeder 20 and the bunker 21. Downspout 24, a pipe extending in the vertical direction directly below bunker 21, holds fuel in a layered state inside, and the layer of solid fuel stacked inside downspout 24 ensures a seal that prevents the primary air and pulverized fuel on the mill 10 side from flowing back toward the bunker 21 side. The amount of solid fuel supplied to the mill 10 is adjusted by, for example, the moving speed of the belt conveyor of the transport unit 22.

[0034] The blower 30 is a device that blows primary air into the housing 11 to dry the pulverized fuel and transport it to the rotary classifier 16 . In this embodiment, the blower section 30 is equipped with a primary air fan (PAF) 31, a hot gas flow path 30a, a cold gas flow path 30b, a hot gas damper 30c, and a cold gas damper 30d in order to appropriately adjust the flow rate and temperature of the primary air blown into the inside of the housing 11.

[0035] The hot gas flow path 30a supplies a portion of the air (outside air) sent out from the primary air fan 31 as hot gas that has been heated by passing through a heat exchanger 34, such as an air preheater. A hot gas damper 30c is provided downstream 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.

[0036] Cold gas flow path 30b supplies a portion of the air sent out from primary air ventilator 31 as cold gas at room temperature. Cold gas damper 30d is provided downstream of cold gas flow path 30b. The opening degree of cold gas damper 30d is controlled by control unit 50. The flow rate of cold gas supplied from cold gas flow path 30b is determined by the opening degree of cold gas damper 30d.

[0037] The flow rate of the primary air is the sum of the flow rate of the hot gas supplied from the hot gas flow path 30a and the flow rate of the cold gas supplied from the cold gas flow path 30b, and 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. In addition, the oxygen concentration of the primary air blown into the inside of the housing 11 from the primary air flow path 100a may be adjusted by introducing and mixing a portion of the combustion gas discharged from the boiler 200 via a gas recirculation ventilator (not shown) into the hot gas supplied from the hot gas flow path 30a.

[0038] The state detection unit 40 of the mill 10 transmits measured or detected data to the control unit 50. The state detection unit 40 is, for example, a differential pressure measurement means, and measures the differential pressure of the mill 10 as the difference between the pressure at the portion where primary air flows from the primary air flow path 100a into the housing 11 and the pressure at the outlet port 19 where the primary air and pulverized fuel are discharged from the housing 11 to the pulverized fuel supply flow path 100b. An increase or decrease in this differential pressure of the mill 10 corresponds to an increase or decrease in the amount of pulverized fuel circulating between the vicinity of the rotary classifier 16 inside the housing 11 and the vicinity of the grinding table 12 due to the classification effect of the rotary classifier 16. In other words, by adjusting the rotation speed of the rotary classifier 16 according to the differential pressure of the mill 10, the amount of pulverized fuel discharged from the outlet port 19 can be adjusted relative to the amount of solid fuel supplied to the mill 10.Therefore, within the range where the particle size of the pulverized fuel does not affect the combustibility of the burner 220, an amount of pulverized fuel corresponding to the amount of solid fuel supplied to the mill 10 can be stably supplied to the burner 220 provided in the boiler 200.

[0039] The state detection unit 40 is, for example, a temperature measurement means, which detects the temperature of the primary air supplied into the housing 11 (the temperature of the primary air at the mill inlet) and the temperature of the primary air from the space above the grinding table 12 inside the housing 11 to the outlet port 19, and controls the blower unit 30 so that the upper limit temperature is not exceeded. The upper limit temperature is determined taking into consideration the possibility of ignition of the solid fuel, etc. The primary air is cooled inside the housing 11 by transporting the pulverized fuel while drying it, and the temperature of the primary air at the outlet port 19 is, for example, about 60 to 90 degrees.

[0040] The discharge device 60 is provided below the mill 10. The discharge device 60 includes a spillage hopper 62 and a spillage chute 64.

[0041] The spillage chute 64 is a duct-like member that extends linearly. The upstream end of the spillage chute 64 is connected to an opening formed in the bottom surface portion 41 of the housing 11, and the downstream end of the spillage chute 64 is connected to the upper part of the spillage hopper 62. Spillage discharged from the mill 10 flows through the inside of the spillage chute 64. The spillage is also stored in the spillage hopper 62. Examples of spillage include foreign matter such as minerals and metal pieces mixed in with the solid fuel, and pulverized solid fuel that is too heavy to be transported by primary air. The spillage hopper 62 stores residual coal discharged from the mill 10 during a clearing operation, which will be described later.

[0042] An inlet valve 64a is provided midway along the spillage chute 64. The inlet valve 64a can switch between an open state and a closed state of a flow path formed inside the spillage chute 64. The inlet valve 64a can switch between a state in which the spillage in the mill 10 is discharged through the spillage chute 64 to the spillage hopper 62 and a state in which it is not discharged.

[0043] The control unit 50 is a device that controls each part of the solid fuel pulverizer 100 . The control unit 50 may, for example, transmit a drive command to the mill motor 15 to control the rotation speed of the grinding table 12. The control unit 50, for example, transmits a drive command to the classifier motor 18 to control the rotational speed of the rotary classifier 16, thereby adjusting the classification performance, and by optimizing the differential pressure of the mill 10, i.e., the amount of pulverized fuel circulating inside the mill 10, within a predetermined range, it is possible to stably supply pulverized fuel to the burner 220. In addition, the control unit 50 can adjust the amount of solid fuel (amount of coal supply) that the conveying unit 22 conveys and supplies to the fuel supply unit 17, for example, by transmitting a drive instruction to the coal supply motor 23 of the coal supply unit 20. Furthermore, the control unit 50 can adjust the flow rate and temperature of the primary air by controlling the opening of the hot gas damper 30c and the cold gas damper 30d by transmitting an opening command to the blower 30. Specifically, the control unit 50 controls the opening of the hot gas damper 30c and the cold gas damper 30d so that the flow rate of the primary air supplied to the inside of the housing 11 and the temperature of the primary air at the outlet port 19 become predetermined values ​​set in accordance with the amount of coal feed for each type of solid fuel. The control unit 50 also controls the discharge device 60, as will be described later.

[0044] The control unit 50 is composed of, for example, a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), and a computer-readable storage medium. A series of processes for implementing various functions is stored in a storage medium, for example, in the form of a program. The CPU reads the program into the RAM and executes information processing and arithmetic operations to implement various functions. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories. The HDD may be replaced with a solid-state disk (SSD), for example.

[0045] Next, a description will be given of the boiler 200 that generates steam by burning the pulverized fuel supplied from the solid fuel pulverizer 100. The boiler 200 includes a furnace 210 and a burner 220.

[0046] The burner 220 is a device that burns pulverized fuel to form a flame using primary air containing pulverized fuel supplied from the pulverized fuel supply passage 100b and secondary air supplied by heating air (outside air) sent out from a forced draft fan (FDF) 32 in a heat exchanger 34. 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 a coal economizer.

[0047] The combustion gas discharged from the boiler 200 undergoes predetermined processing in an environmental device (such as a denitration device or an electrostatic precipitator, not shown), and then undergoes heat exchange in a heat exchanger 34, such as an air preheater, between the air discharged from the primary air fan 31 and the air discharged from the forced draft fan 32, and is then guided to a chimney (not shown) via an induced draft fan (IDF) 33 and released into the outside air. The air discharged from the primary air fan 31, heated by the combustion gas in the heat exchanger 34, is supplied to the above-mentioned hot gas flow path 30a. The water supplied to each heat exchanger of the boiler 200 is heated in a coal economizer (not shown), and then further heated in an evaporator (not shown) and a superheater (not shown) to generate high-temperature, high-pressure steam, which is then sent to the power generation section, a steam turbine (not shown), to rotate and drive the steam turbine, which then rotates and drives a generator (not shown) connected to the steam turbine to generate electricity, thereby constituting the power generation plant 1.

[0048] Next, the spillage hopper 62 will be described in detail with reference to FIGS. The spillage hopper 62 according to this embodiment is a so-called wet-type spillage hopper that transports stored materials by hydraulic transport. As shown in Figures 2 and 3, the spillage hopper 62 includes a housing (main body) 66 that temporarily stores spillage, residual coal, etc. as stored materials inside, and a seal part 68 connected to the side wall part of the housing 66. A spillage chute 64 is connected to the top of the housing 66, and a discharge pipe (not shown) is connected to the bottom of the housing 66. When the inlet valve 64a is opened, spillage is guided from the inside of the mill 10 into the inside of the housing 66 through the spillage chute 64.

[0049] The housing 66 is a box-shaped member having an internal space. The housing 66 integrally comprises a circular ceiling 71 that defines the upper side of the space, a side wall 72 that extends downward from the outer circumferential edge of the ceiling 71 and defines the sides of the space, and an inverted truncated cone-shaped bottom 73 that extends downward from the lower end of the side wall 72 and has an inclined surface that defines the lower side of the space. As shown in Figure 2, an inlet 74 is formed in a part of the ceiling 71. The inlet 74 is connected to the spillage chute 64. Furthermore, a discharge outlet 75 is formed at the lower end of the bottom 73. A discharge pipe (not shown) extending downward from the lower end of the bottom 73 is connected to the discharge outlet 75. The discharge pipe discharges the material stored inside the housing 66 to an ash dump or other location outside the system. The discharge pipe is provided with a discharge mechanism, such as a water jet pump, that switches the state of discharge to outside the system.

[0050] A first input port 71a, which is an opening that penetrates in the vertical direction, is formed in the ceiling portion 71. A vacuum hose, which will be described later, is inserted into the first input port 71a.

[0051] A second input port 72a, which is an opening that penetrates horizontally, is formed in the side wall portion 72. A vacuum hose, which will be described later, is inserted into the second input port 72a. The second input port 72a is located above a wire mesh 67, which will be described later.

[0052] Furthermore, a wire mesh 67 is provided within the housing 66. The wire mesh 67 is provided in the vertical center of the housing 66. The wire mesh 67 is provided so as to cover the horizontal cross section of the housing 66. The wire mesh 67 is provided in an inclined state with one end downward toward the second insertion port 72a. Note that the wire mesh 67 may also be provided horizontally without being inclined. The wire mesh 67 is provided so as to divide the internal space of the housing 66 in the vertical direction. An opening / closing section (not shown) is provided in a part of the wire mesh 67. The opening / closing section is, for example, a door-shaped part of the wire mesh 67. When the opening / closing section is in an open state, an opening large enough to allow a vacuum hose (described later) to pass through is formed in the wire mesh 67. When the opening / closing section is in a closed state, the opening is closed.

[0053] The ceiling portion 71 is provided with a jet nozzle 76 that jets water downward. Water (hereinafter also referred to as "assist water") is jetted from the jet nozzle 76. The jet angle of the jet nozzle 76 is set to an angle that allows the water to reach the entire horizontal cross section of the housing 66, as shown in FIG. 2. The assist water sprayed from the spray nozzle 76 is sprayed toward the accumulated material accumulated on the upper surface of the wire mesh 67 provided in the housing 66. Note that when the discharge port 75 is closed or when the amount of assist water sprayed from the spray nozzle 76 exceeds the amount sent out from the discharge port 75 to the outside of the system, the assist water is stored as accumulated material in the housing 66.

[0054] Furthermore, a connection pipe 78 is provided on the ceiling portion 71. One end of the connection pipe 78 is connected to the ceiling portion 71, and the other end is connected to the spillage chute 64. In other words, the connection pipe 78 communicates between the internal space of the housing 66 and the internal space of the spillage chute 64.

[0055] 3, an outlet 72b to which a seal pipe 80, which will be described later, is connected is formed in the upper part of the side wall portion 72. The outlet 72b is formed above the second input port 72a.

[0056] 3, the seal unit 68 is connected at one end via a seal pipe 80 to an upper portion of the side wall portion 72 of the housing 66, to a seal pot 82 that extends vertically downward and has an opening at its lower end. The seal unit 68 also has an overflow pipe 84 that has one end connected to the upper portion of the seal pot 82 and the other end extending downward, and a seal water supply pipe 86 that is connected to the lower end of the seal pot 82 and supplies seal water to the inside of the seal pot 82. The seal unit 68 maintains the pressure inside the housing 66 and the mill 10 at a predetermined pressure by sealing with water.

[0057] The opening at the lower end of the vertical section of the seal pipe 80 opens into the seal pot 82. The vertical section of the seal pipe 80 and the seal pot 82 are filled with seal water. When the pressure inside the housing 66 and the mill 10 changes, the water level of the seal water in the vertical section of the seal pipe 80 and the seal pot 82 changes. When the water level of the seal water in the seal pot 82 rises, the seal unit 68 discharges the seal water from the seal pot 82 via the overflow pipe 84. When the water level of the seal water in the seal pot 82 drops, the seal unit 68 replenishes the seal water into the seal pot 82 via the seal water supply pipe 86. The seal unit 68 suppresses changes in pressure inside the housing 66 and the mill 10 by discharging and replenishing the seal water from the seal pot 82.

[0058] Furthermore, the discharge port 72b and the seal pipe 80 control and define the upper limit of the amount of stored material (spillage, assist water, residual carbon, etc.) that can be stored within the housing 66. That is, as stored material accumulates within the housing 66, when the accumulated material reaches the height of the discharge port 72b, it is discharged from the housing 66 via the discharge port 72b and the seal pipe 80. Therefore, the amount of stored material that can be stored within the housing 66 does not exceed the upper limit. In this way, the discharge port 72b and the seal pipe 80 define the upper limit of the amount of stored material that can be stored within the housing 66.

[0059] As shown in FIGS. 3 to 6, a cover 90 is provided on the inner circumferential surface of the side wall portion 72 of the housing 66 to cover the discharge port 72b.

[0060] The cover 90 has a pair of first wall portions 90a that protrude radially inward from the inner surface of the side wall portion 72 of the housing 66, a second wall portion 90b that connects the inner ends (tips) of the pair of first wall portions 90a, and a bottom surface portion 90c that connects the lower ends of the pair of first wall portions 90a and the lower ends of the second wall portion 90b.

[0061] The cover 90 defines a space inside the cover 90. The space is open at the top. That is, a communication port 90d is formed at the top end of the cover 90, which connects the space inside the cover 90 with the space outside the cover 90. The interior space of the cover 90 is defined laterally by a first wall portion 90a, a second wall portion 90b, and the side wall portion 72. The lower end is closed by a bottom surface portion 90c. The discharge port 72b opens into this space. In this way, the cover 90 has a box shape that is open at the top.

[0062] The first wall portion 90a is a plate-shaped member and is disposed so that the plate surface is a vertical plane. The second wall portion 90b is a plate-like member, and the plate surface of the second wall portion 90b is a vertical surface, and the second wall portion 90b is disposed so as to connect the inner ends (tips) of the pair of first wall portions 90a to each other. The bottom surface portion 90c is a plate-shaped member. The bottom surface portion 90c is arranged so that the plate surface is horizontal. The upper surface of the bottom surface portion 90c is arranged to connect the lower ends of the pair of first wall portions 90a and second wall portions 90b.

[0063] The upper end of the cover 90 is close to and faces the inner surface of the ceiling portion 71. The upper end of the cover 90 and the ceiling portion 71 are spaced apart.

[0064] [Clearing Operation] Next, the clearing operation of the mill 10 will be described. In some cases, such as when the operation of the boiler 200 is stopped urgently or when an abnormality occurs in the mill 10, the operation of the mill 10 may be quickly stopped (emergency stop). When the mill 10 is stopped urgently, solid fuel (such as coal) and its pulverized material that was supplied immediately before the shutdown remain inside the mill 10, such as on the grinding table 12. If the mill 10 is left with the solid fuel and pulverized material (hereinafter referred to as "residual charcoal") remaining inside the mill 10, the residual charcoal may ignite due to spontaneous oxidation and temperature rise. Furthermore, if the mill 10 is restarted while residual charcoal remains, the residual charcoal may rapidly combust due to the high-temperature carrier gas supplied to the mill 10 upon restart. Therefore, to prevent this, when the mill 10 is stopped urgently, the residual charcoal must be discharged from the mill 10. Therefore, after the emergency shutdown of the mill 10, a clearing operation is performed to discharge the residual charcoal from the inside of the mill 10.

[0065] The clearing operation in this embodiment is outlined below. During the clearing operation, the supply of primary air from the primary air flow path 100a is stopped, and the crushing table 12 is rotated, causing the residual coal on the crushing table 12 to fall from the outer periphery of the crushing table 12 to the bottom surface 41 of the housing 11 by centrifugal force. The residual coal that has fallen to the bottom surface is discharged by a scraper from the inside of the mill 10 through the spillage chute 64 to the spillage hopper 62. The residual coal discharged to the spillage hopper 62 is stored as a deposit in the housing 66.

[0066] At this time, part of the remaining charcoal (retained material) discharged into the spillage hopper 62 accumulates in a mountain-like shape on the upper surface of the wire mesh 67. In order to break up the mountain of remaining charcoal (retained material), assist water is sprayed from the spray nozzle 76 toward the accumulated remaining charcoal (retained material).

[0067] [Residual carbon disposal method] Next, a method for treating the residual carbon (retained matter) introduced into the spillage hopper 62 will be described. The spillage hopper 62 discharges the residual carbon (retained matter) introduced into the interior thereof to the outside of the spillage hopper 62 by, for example, sucking it with a vacuum hose introduced into the spillage hopper 62 . The vacuum hose may simultaneously suck up accumulated materials other than the residual carbon and discharge them outside the spillage hopper 62, or may suck up only accumulated materials other than the residual carbon and discharge them outside the spillage hopper 62.

[0068] Specifically, first, the tip end of a vacuum hose is inserted into the inside of the spillage hopper 62 through the first insertion port 71a formed in the ceiling portion 71 of the spillage hopper 62. Then, the vacuum hose is used to suck up the remaining charcoal (retained material) accumulated on the upper surface of the wire mesh 67 and discharge it outside the spillage hopper 62. Once the remaining charcoal (retained material) accumulated on the upper surface of the wire mesh 67 has been sucked up, the vacuum hose is temporarily removed from inside the spillage hopper 62.

[0069] Next, the opening / closing portion (not shown) of the wire mesh 67 is opened through the second input port 72a formed in the side wall portion 72 of the spillage hopper 62. Then, the tip of the vacuum hose is input into the inside of the spillage hopper 62 through the second input port 72a, and the tip of the vacuum hose is passed through the opening / closing portion of the wire mesh 67. As a result, the tip of the vacuum hose is input into the space below the wire mesh 67. Then, the vacuum hose sucks up the residual charcoal (retained material) accumulated below the wire mesh 67 and discharges it outside the spillage hopper 62. After sucking up the residual charcoal (retained material) accumulated below the wire mesh 67, the vacuum hose is removed from inside the spillage hopper 62. Then, the opening / closing portion of the wire mesh 67 is closed.

[0070] The spillage hopper 62 may discharge the residual carbon (retained matter) introduced into the interior thereof, for example, via a discharge pipe to the exterior from a discharge port 75. In this case, instead of a vacuum hose, a hose or the like for supplying assist water may be inserted into the space below the wire mesh 67 through the opening and closing portion of the wire mesh 67.

[0071] According to this embodiment, the following advantageous effects are achieved. In this embodiment, a cover 90 is provided that covers the discharge port 75. As a result, even if the amount of stored material increases and reaches the height of the discharge port 75, the cover 90 covering the discharge port 75 prevents the stored material from being discharged to the outside of the housing 66 through the discharge port 75. Furthermore, in this embodiment, the cover 90 is formed with a communication port 90d above the discharge port 75 that connects the interior space of the cover 90 with the exterior space of the cover 90. As a result, as the amount of stored material in the housing 66 further increases, the stored material flows into the interior space of the cover 90 through the communication port 90d. The stored material that flows into the interior space of the cover 90 is discharged to the outside of the housing 66 through the discharge port 75. In this way, in this embodiment, the stored material can be stored in the housing 66 up to the height of the communication port 90d, which is located above the discharge port 75. Therefore, the amount of stored material that can be stored in the housing 66 can be increased.

[0072] In this embodiment, a connection pipe 78 is provided that connects the portion of the housing 66 above the communication port 90d with the spillage chute 64. This allows air at the upper end of the interior of the housing 66 to be guided to the spillage chute 64 via the connection pipe 78. Therefore, the stored material is stored inside the housing 66 up to near the ceiling, making it less likely that an air pocket will form between the ceiling and the stored material. This prevents the stored material from reaching the communication port 90d due to an air pocket. Therefore, even in a spillage hopper 62 equipped with a cover 90, the upper limit of the stored material can be appropriately managed. This prevents the stored material from flowing back through the spillage hopper 62.

[0073] In this embodiment, the ceiling of the housing 66 is provided with an injection nozzle 76 that injects assist water into the interior of the housing 66. As a result, even if accumulated matter has piled up in a mountain shape inside the housing 66 (i.e., if accumulated matter is unevenly piled up in one area), the pile of accumulated matter can be broken up by the assist water. Therefore, uneven accumulation of accumulated matter can be reduced.

[0074] If an inlet through which a vacuum hose can be inserted is formed on the side of the housing 66, and if the accumulated material extends above the inlet, opening the inlet will cause the accumulated material to close the inlet, making it difficult to insert the vacuum hose. On the other hand, in this embodiment, a first insertion port 71a through which the vacuum hose can be inserted is formed in the ceiling portion 71. This makes it less likely that the insertion port will be blocked by accumulated material. Therefore, the vacuum hose can be inserted into the housing 66 in an optimal manner.

[0075] The present disclosure is not limited to the invention according to the above-described embodiment, and various modifications are possible within the scope of the present disclosure. For example, the solid fuel used is not limited to that disclosed herein, and may be coal, biomass fuel, petroleum coke (PC), etc. Furthermore, these solid fuels may be used in combination.

[0076] The spillage hopper, the crusher, and the method of operating the spillage hopper described in the above-described embodiment can be understood, for example, as follows. The spillage hopper according to the first aspect of the present disclosure comprises a main body (66) that stores therein the discharged material discharged from a crusher (10), a discharge outlet (72b) formed in a side wall (72) of the main body (66), and a covering (90) that covers the discharge outlet (72b) inside the main body (66) and forms a space inside, the discharge outlet (72b) opens into the space and controls the upper limit amount of the stored material stored inside the main body (66), the covering (90) has side wall (90a, 90b) that define the sides of the space and a bottom (90c) that closes the lower side of the space, and a communication port (90d) that connects the space with a space outside the covering (90) is formed above the discharge outlet (72b).

[0077] The above configuration includes a covering portion that covers the discharge port. As a result, even if the amount of stored material increases and reaches the height of the discharge port, the covering portion that covers the discharge port prevents the stored material from being discharged to the outside of the main body through the discharge port. Furthermore, in the above configuration, the covering portion has a communication port formed above the discharge port that connects the internal space of the covering portion with the external space of the covering portion. As a result, as the amount of stored material in the main body increases further, the stored material flows into the internal space of the covering portion through the communication port. The stored material that flows into the internal space of the covering portion is discharged to the outside of the main body portion through the discharge port. In this way, the above configuration allows the stored material to be stored in the main body portion until it reaches the height of the communication port, which is located above the discharge port. Therefore, the amount of stored material that can be stored in the main body can be increased.

[0078] In addition, in the spillage hopper according to the second aspect of the present disclosure, in the first aspect described above, the main body (66) is provided with an inlet (74) located below the communication port (90d) and connected to a spillage chute (64) that connects the main body (66) to the crusher (10) and through which the discharge flows, and a connecting pipe (78) that connects the part of the main body (66) above the communication port (90d) to the spillage chute (64).

[0079] The above-described configuration includes a connecting pipe that connects the portion of the main body above the communication port with the spillage chute. This allows the accumulated material to accumulate inside the main body up to near the ceiling, making it less likely that air will accumulate between the ceiling and the accumulated material. This prevents the accumulated material from reaching the communication port due to air accumulation. Therefore, even in a spillage hopper equipped with a covering, the upper limit of the accumulated material can be appropriately managed. This prevents the accumulated material (discharged material) from flowing back through the spillage hopper.

[0080] In addition, the spillage hopper according to the third aspect of the present disclosure is the same as that of the first or second aspect, except that the ceiling portion (71) of the main body portion (66) is provided with an injection nozzle (76) that injects assist water into the inside of the main body portion (66).

[0081] In the above configuration, the ceiling of the main body is provided with an injection nozzle that injects assist water into the main body. As a result, even if the accumulated material accumulates in a mountain shape inside the main body (i.e., if the accumulated material is unevenly accumulated in one area), the pile of accumulated material can be broken up by the assist water. Therefore, uneven accumulation of the accumulated material can be reduced.

[0082] In addition, in the spillage hopper according to the fourth aspect of the present disclosure, in any of the first to third aspects, an inlet (71a) is formed in the ceiling portion (71) of the main body portion (66), which connects the internal space of the main body portion (66) with the external space and through which a vacuum hose can be inserted to suck up the accumulated material inside the main body portion (66).

[0083] If an inlet through which a vacuum hose can be inserted is formed on the side of the main body, and if the accumulated material extends above the inlet, opening the inlet will cause the accumulated material to close the inlet, making it difficult to insert the vacuum hose. On the other hand, in the above configuration, an inlet through which the vacuum hose can be inserted is formed in the ceiling portion, which makes it less likely that the inlet will be blocked by accumulated material, and therefore the vacuum hose can be inserted into the main body in an optimal manner.

[0084] A pulverizer according to a first aspect of the present disclosure includes a pulverizer body and the spillage hopper according to any one of the first to fourth aspects.

[0085] A method for operating a crusher according to a first aspect of the present disclosure is a method for operating a spillage hopper (62), the spillage hopper (62) comprising a main body (66) for storing therein discharged material discharged from a crusher (10), a discharge outlet (72b) formed in a side wall (72) of the main body (66), and a covering (90) for covering the discharge outlet (72b) inside the main body (66) and forming a space inside, the discharge outlet (72b) opening into the space and controlling the upper limit of the amount of stored material stored inside the main body (66), the covering (90) having side wall (90a, 90b) defining the sides of the space and a bottom (90c) closing the lower side of the space, and a communication port (90d) for connecting the space with a space outside the covering (90) is formed above the discharge outlet (72b). [Explanation of symbols]

[0086] 1: Power plant 10: Mill 11: Housing 12: Grinding table 13: Crushing roller 14: Drive unit 15: Mill motor 16: Rotary classifier 16a: Blade 17:Fuel supply section 18: Classifier motor 19: Exit port 20:Coal feeding machine 21: Banka 22: Transport unit 23: Coal feeder motor 24: Downspout 30: Blower 30a: Hot gas flow path 30b: Cold gas flow path 30c: Thermal gas damper 30d: Cold gas damper 31: Primary air ventilator 32: Forced ventilation fan 33: Induced draft fan 34:Heat exchanger 40: Status detection unit 41: Bottom part 42: Ceiling 45: Journal head 47: Support arm 48: Support shaft 49: Pressing device 50: Control unit 60: Discharge device 62: Spillage Hopper 64: Spillage Shoot 64a: Inlet valve 66: Housing (main body) 67: Wire mesh 68: Seal part 71: Ceiling 71a: 1st input port 72: Side wall 72a: 2nd input port 72b: Outlet 73: Bottom 74: Entrance 75: Outlet 76: Injection nozzle 78: Connection piping 80: Seal pipe 82: Seal pot 84: Overflow pipe 86: Seal water supply pipe 90: Cover 90a: First wall portion 90b: 2nd wall part 90c: Bottom part 90d: Communication port 100: Solid fuel crusher 100a: Primary air flow path 100b: Pulverized fuel supply passage 200: Boiler 210: Furnace 220: Burner

Claims

1. a main body that stores waste material discharged from the crusher; an outlet formed in a side wall of the main body; a covering portion that covers the outlet inside the main body portion and forms a space inside the main body portion, the outlet is open to the space and controls an upper limit of the amount of the material stored inside the main body portion; The covering portion has a side wall portion that defines the sides of the space and a bottom portion that closes the lower part of the space, and a communication port is formed above the discharge outlet that connects the space with the space outside the covering portion.

2. the main body has an inlet located below the communication port, which connects the main body to the crusher and to which a spillage chute is connected, through which the discharged material flows; 2. The spillage hopper according to claim 1, further comprising a connecting pipe connecting a portion of said main body portion above said communication port to said spillage chute.

3. 2. The spillage hopper according to claim 1, wherein a spray nozzle for spraying assist water into the interior of the main body is provided on a ceiling of the main body.

4. 2. The spillage hopper according to claim 1, wherein the ceiling of the main body has an inlet that connects the internal space of the main body with the external space and through which a vacuum hose can be inserted to suck up the material stored inside the main body.

5. A crusher body, A crusher comprising the spillage hopper according to any one of claims 1 to 4.

6. 1. A method of operating a spillage hopper, comprising: The spillage hopper is a main body that stores waste material discharged from the crusher; an outlet formed in a side wall of the main body; a covering portion that covers the outlet inside the main body portion and forms a space inside the main body portion, the outlet is open to the space and controls the upper limit of the amount of the stored material stored inside the main body portion; A method for operating a spillage hopper, wherein the covering portion has side wall portions that define the sides of the space and a bottom portion that closes the lower part of the space, and a communication port that connects the space with a space outside the covering portion is formed above the discharge outlet.

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