JP2024067391A - Crushing roller, crushing table, solid fuel crushing device, and method of manufacturing the crushing roller - Google Patents

Abstract

[Problem] To improve the yield rate when manufacturing a grinding roller and a grinding table, and to extend the life of the grinding roller and the grinding table. [Solution] A grinding roller 13 includes a journal housing 43 rotatably supported by the housing, and an annular roller portion 49 fixed to the journal housing 43 and grinding solid fuel between the journal housing 43 and the grinding table. The roller portion 49 includes a base portion 51 fixed to the journal housing, and a ceramic portion 52 provided on the outer periphery of the base portion 51, which has a linear expansion coefficient different from that of the base portion 51 and is more wear-resistant than the base portion 51. The ceramic portion 52 includes first ceramic particles 52c and second ceramic particles 52d which have different rigidity and toughness from the first ceramic particles 52c, and the mixture ratio of the first ceramic particles 52c and the second ceramic particles 52d changes along the direction of the rotation center axis C2. [Selected Figure] Fig. 3

Description

This disclosure relates to a grinding roller, a grinding table, a solid fuel grinding device, and a method for manufacturing a grinding roller.

Conventionally, solid fuels such as biomass fuels and coal are pulverized into fine powder within a specified particle size range by a pulverizer (mill) and then supplied to a combustion device. In the mill, the solid fuel fed onto the pulverization table is pinched between the pulverization table and the pulverization rollers to pulverize it, and fine fuel within a specified particle size range is selected by a classifier from the pulverized solid fuel in fine powder form. The fine fuel is transported to a boiler by a carrier gas (primary air) supplied from the periphery of the pulverization table, and is burned in the combustion device. In a thermal power plant, steam is generated by heat exchange with the combustion gas generated by burning the pulverized fuel in the boiler, and the steam is used to rotate and drive a steam turbine, which then rotates and drives a generator connected to the steam turbine to generate electricity.

As a grinding roller provided in a mill, a ceramic-embedded grinding roller and grinding table are known in which a highly wear-resistant ceramic is embedded in a portion that comes into contact with the solid fuel (for example, see Patent Document 1). Such ceramic-embedded grinding rollers and grinding tables are superior in wear resistance and allowable wear amount compared to conventional grinding rollers and grinding tables, and can be expected to have a longer life.
Patent Document 1 describes a crushing member that includes a high Cr steel support having a continuous support wall that forms a polygonal space, and a ceramic member that is disposed within the space of the high Cr steel support.

JP 2013-173129 A

When manufacturing ceramic-embedded grinding rollers or grinding tables, first, particulate ceramics (hereinafter referred to as "ceramic particles") are molded into a block shape to produce a ceramic block that constitutes part of the ceramic portion. Next, with the ceramic block placed in a designated position in the mold, molten metal is poured into the mold. The metal in the mold is then cooled and solidified. In this way, ceramic-embedded grinding rollers or grinding tables are manufactured in which the ceramic portion (portion containing ceramic) and base (portion not containing ceramic) are fixed together.

When cooling the metal in the mold, damage due to thermal contraction is a concern. The ceramic part has a smaller linear expansion coefficient than the metal in the mold. Therefore, the ceramic part shrinks less than the base when cooled. Therefore, the ceramic part and the base shrink differently when cooled. At this time, since the ceramic part and the base are integrated, the base tries to shrink the ceramic part, and the ceramic part tries to suppress the shrinkage of the base. Therefore, thermal stress acts on the inside of the base and ceramic part, and the grinding roller or grinding table may be damaged. In this way, ceramic-embedded grinding rollers and grinding tables may be damaged during manufacturing due to the difference in linear expansion coefficient between the ceramic part and the base. Therefore, there is a possibility that the yield rate when manufacturing grinding rollers and grinding tables may decrease.

When the rigidity of a member is reduced or the toughness is increased, the member becomes more stretchable. Therefore, the stress generated when the same displacement is applied is kept low, and the thermal stress is reduced. Therefore, in order to reduce the internal thermal stress of the ceramic embedded type grinding roller or grinding table, it is possible to reduce the rigidity of the ceramic part or increase the toughness. However, when the rigidity of the ceramic part is reduced or the toughness is increased, the wear resistance and allowable wear amount of the grinding roller or grinding table are reduced, which is a problem in that the life of the grinding roller or grinding table is shortened.
Under these circumstances, it has been desired to improve the yield rate in manufacturing the crushing rollers and the crushing tables, and to extend the life of the crushing rollers and the crushing tables.

The present disclosure has been made in consideration of these circumstances, and aims to provide a crushing roller, a crushing table, and a solid fuel crushing device, as well as a method for manufacturing a crushing roller, that can improve the yield rate when manufacturing the crushing roller and the crushing table and extend the life of the crushing roller and the crushing table.

In order to solve the above problems, the crushing roller, the crushing table, the solid fuel crushing device, and the method of manufacturing the crushing roller of the present disclosure employ the following measures.
A grinding roller according to one embodiment of the present disclosure is a grinding roller that is housed inside a housing, pinches solid fuel between itself and a rotating grinding table to grind the solid fuel, and rotates about a rotation axis when subjected to a rotational force from the grinding table, the grinding roller comprising: a support portion rotatably supported relative to the housing; and an annular roller portion fixed to the support portion and grinds the solid fuel between itself and the grinding table, the roller portion having a base portion fixed to the support portion and a ceramic portion provided on the outer periphery of the base portion, the ceramic portion having a linear expansion coefficient different from that of the base portion and having superior wear resistance to the base portion, the ceramic portion having a first ceramic and a second ceramic having rigidity and toughness different from those of the first ceramic, and a mixing ratio of the first ceramic to the second ceramic changing along the direction of the rotation axis.

A method for manufacturing a grinding roller according to one aspect of the present disclosure is a method for manufacturing a grinding roller that is housed inside a housing, that grinds solid fuel by sandwiching the solid fuel between the grinding roller and a rotating grinding table, and that rotates around a rotation axis when it receives a rotational force from the grinding table, the grinding roller includes a support portion that is rotatably supported by the housing, and an annular roller portion that is fixed to the support portion and grinds the solid fuel between the grinding roller and the grinding table, the roller portion includes a base portion that is fixed to the support portion, and a ceramic portion that is provided on the outer periphery of the base portion and has a linear expansion coefficient different from that of the base portion and is more wear-resistant than the base portion, the ceramic portion includes a first ceramic and a second ceramic that has a rigidity and toughness different from that of the first ceramic, the mixing ratio of the first ceramic and the second ceramic changes along the direction of the rotation axis, and the method includes a step of integrally molding the base portion and the ceramic portion by casting.

This disclosure makes it possible to improve the yield rate when manufacturing grinding rollers and grinding tables, and to extend the lifespan of the grinding rollers and grinding tables.

FIG. 2 is a configuration diagram showing a solid fuel pulverizer and a boiler according to the first embodiment of the present disclosure. FIG. 2 is a schematic side view of a crushing roller provided in the solid fuel crushing device according to the first embodiment of the present disclosure. 1 is a cross-sectional view of a main portion of a crushing roller according to a first embodiment of the present disclosure. 10 is a cross-sectional view of a main portion of a crushing roller according to a modified example of the first embodiment of the present disclosure. FIG. FIG. 13 is a perspective view of a roller portion according to a modified example of the first embodiment of the present disclosure. FIG. 6 is an enlarged view of a portion VI in FIG. 5 . FIG. 7 is a diagram showing a modification of FIG. 6 . FIG. 2 is a schematic vertical cross-sectional view of a grinding table provided in the solid fuel grinding device according to the first embodiment of the present disclosure. FIG. 9 is an enlarged view of part IX in FIG. 8 . FIG. 2 is a schematic diagram showing a mold for manufacturing the crushing roller according to the first embodiment of the present disclosure. FIG. 11 is a diagram showing a modification of FIG. 10 . FIG. 11 is a diagram showing a modification of FIG. 10 . FIG. 2 is a schematic side view of the crushing roller according to the first embodiment of the present disclosure, showing the progress of wear. FIG. 6 is a cross-sectional view of a main portion of a crushing roller according to a second embodiment of the present disclosure. FIG. 15 is a diagram showing a modified example of FIG. 14 . FIG. 11 is a diagram showing the position in the direction of the rotation center axis of a crushing roller according to a second embodiment of the present disclosure. 13 is a graph showing the required wear resistance and the mixture ratio of ceramic particles at the position in the direction of the rotation center axis of the grinding roller according to the second embodiment of the present disclosure.

Below, an embodiment of the grinding roller, grinding table, solid fuel grinding device, and grinding roller manufacturing method according to the present disclosure will be described with reference to the drawings.

First Embodiment
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present disclosure will now be described with reference to the drawings. A power plant 1 according to this embodiment includes a solid fuel pulverizer 100 and a boiler 200.
In the following explanation, "upper" refers to the vertically upper direction, and "upper" in terms such as upper part and upper surface refers to the vertically upper part. Similarly, "lower" refers to the vertically lower part, and the vertical direction is not precise and may include errors.

The solid fuel pulverizing device 100 of this embodiment is a device that pulverizes solid fuel, such as biomass fuel or coal, 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.

The solid fuel pulverizing device 100 of this embodiment includes a mill (pulverizing section) 10, a bunker (storage section) 21, a coal feeder (fuel supplying machine) 25, a blower section (carrier gas supplying section) 30, a status detection section 40, and a control section 50.

The mill 10, which pulverizes solid fuel such as coal or biomass fuel to be supplied to the boiler 200 into fine fuel, which is a finely powdered solid fuel, may be of a type that pulverizes only coal, may be of a type that pulverizes only biomass fuel, or may be of a type that pulverizes biomass fuel together with coal.
Here, biomass fuels are 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 are not limited to the ones presented here.Biomass fuels are carbon neutral, meaning they do not emit carbon dioxide, a greenhouse gas, because they capture carbon dioxide during the biomass growth process, and various uses for them are being considered.

The mill 10 comprises a housing 11, a grinding table 12, grinding rollers 13, a reducer (drive transmission unit) 14, a mill motor (drive unit) 15 connected to the reducer 14 and driving the grinding table 12 to rotate, a rotary classifier (classification unit) 16, a coal supply pipe (fuel supply unit) 17, and a classifier motor 18 that drives the rotary classifier 16 to rotate.
The housing 11 is formed in a cylindrical shape extending in the vertical direction, and is a case that accommodates the grinding table 12, the grinding rollers 13, the rotary classifier 16, and the coal supply pipe 17.
A coal feed pipe 17 is attached to the center of the ceiling portion 42 of the housing 11. This coal feed pipe 17 supplies solid fuel guided from the bunker 21 via the coal feeder 25 into the housing 11. The coal feed pipe 17 is disposed in the vertical direction at the center position of the housing 11 and has a lower end extending into the interior of the housing 11.

A reduction gear 14 is provided near the bottom surface 41 of the housing 11, and the grinding table 12 is rotatably disposed and rotated by the driving force transmitted from a mill motor 15 connected to the reduction gear 14.
The grinding table 12 is a circular member in a plan view, and is arranged so that the lower end of the coal supply pipe 17 faces the grinding table 12. The upper surface of the grinding table 12 may have an inclined shape that is low in the center and high toward the outside, and the outer periphery may have a shape that is bent upward. The coal supply pipe 17 supplies solid fuel (for example, coal or biomass fuel in this embodiment) from above toward the grinding table 12 below, and the grinding table 12 pinches the supplied solid fuel between the grinding roller 13 and grinds it.

When solid fuel is fed from the coal feed pipe 17 toward the center of the grinding table 12, the centrifugal force generated by the rotation of the grinding table 12 guides the solid fuel to the outer periphery of the grinding table 12, where it is pinched and ground between the grinding table 12 and the grinding rollers 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) 110, and is guided to the rotary classifier 16.
An outlet (not shown) is provided on the outer periphery of the grinding table 12, through which the primary air flowing in from the primary air passage 110 flows out into the space above the grinding table 12 in the housing 11. A swirling blade (not shown) is provided at the outlet, which applies a swirling force to the primary air blown out from the outlet. The primary air given a swirling force by the swirling blade becomes an airflow having a swirling velocity component, and conveys the solid fuel pulverized on the grinding table 12 to the rotary classifier 16 located at the upper part in the housing 11. Among 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, are returned to the grinding table 12, and are pulverized again between the grinding table 12 and the grinding roller 13.

The crushing roller 13 is a rotating body that crushes the solid fuel supplied onto the crushing table 12 from the coal supply pipe 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.
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 where the three crushing rollers 13 come into contact with the upper surface of the crushing table 12 (pressing portions) are equidistant from the central axis of rotation of the crushing table 12.

The crushing roller 13 can be swung and displaced up and down by the journal head 45, and is supported so that it can move toward and away from the upper surface of the crushing table 12. When the crushing table 12 rotates with its outer circumferential surface in contact with the solid fuel on the upper surface of the crushing table 12, the crushing roller 13 receives a rotational force from the crushing table 12 and rotates with it. When solid fuel is supplied from the coal supply pipe 17, the solid fuel is pressed between the crushing roller 13 and the crushing table 12 and crushed. This pressing force is called the crushing load.

The support arm 47 of the journal head 45 is supported on the side of the housing 11 by a support shaft 48 whose middle part is aligned horizontally, so that the crushing roller 13 can be swung and displaced in the vertical direction around the support shaft 48. A pressing device (crushing load applying part) 46 is provided at the upper end part on the vertically upper side of the support arm 47. The pressing device 46 is fixed to the housing 11, and applies a crushing 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. The crushing load is applied, for example, by a hydraulic cylinder (not shown) operated by the pressure of hydraulic oil supplied from a hydraulic device (not shown) installed outside the mill 10. The crushing load may also be applied by the repulsive force of a spring (not shown).

The reducer 14 is connected to the mill motor 15 and transmits the driving force of the mill motor 15 to the grinding table 12, causing the grinding table 12 to rotate around its central axis.

The rotary classifier (classifying section) 16 is provided at the top of the housing 11 and has a hollow inverted cone-like outer shape. The rotary classifier 16 is provided with a plurality of blades 16a extending in the vertical direction at its outer periphery. The blades 16a are provided at predetermined intervals (equally spaced) around the central axis of the rotary classifier 16.
The rotary classifier 16 is a device that classifies the solid fuel pulverized by the pulverizing table 12 and the pulverizing rollers 13 (hereinafter, the pulverized solid fuel is referred to as "pulverized fuel") into particles larger than a predetermined particle size (for example, 70 to 100 μm for coal) (hereinafter, the pulverized fuel exceeding the predetermined particle size is referred to as "coarse pulverized fuel") and particles smaller than the predetermined particle size (hereinafter, the pulverized fuel smaller than the predetermined particle size is referred to as "fine pulverized fuel"). The rotary classifier 16 is given a rotational driving force by a classifier motor 18 controlled by the control unit 50, and rotates around a coal feed pipe 17 centered on a cylindrical axis (not shown) extending in the vertical direction of the housing 11.
The classifying section may be a fixed classifier having a fixed hollow inverted cone-shaped casing and a plurality of fixed swirling vanes on the outer periphery of the casing instead of the blades 16a.

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, the large diameter coarse pulverized fuel is knocked down by the blades 16a and returned to the grinding table 12 for re-pulverization, and the fine pulverized fuel is led to the outlet port 19 in the ceiling 42 of the housing 11. The fine pulverized fuel classified by the rotary classifier 16 is discharged together with the primary air from the outlet port 19 into the fine fuel supply passage (fine fuel supply pipe) 120 and supplied to the burner 220 of the boiler 200.

The coal supply pipe 17 is attached so that its lower end extends vertically into the interior of the housing 11, penetrating the ceiling 42 of the housing 11, and supplies solid fuel fed from the top of the coal supply pipe 17 to the center of the grinding table 12. A coal supply machine 25 is connected to the upper end of the coal supply pipe 17, through which solid fuel is supplied.

The charcoal feeder 25 is connected to the bunker 21 by the downspout 22, which is a pipe extending vertically from the lower end of the bunker 21. A valve (coal gate, not shown) for switching the discharge state of the solid fuel from the bunker 21 may be provided midway through the downspout 22. The charcoal feeder 25 includes a conveying section 26 and a charcoal feeder motor 27. The conveying section 26 is, for example, a belt conveyor, and conveys the solid fuel discharged from the lower end of the downspout 22 to the upper part of the charcoal feeder pipe 17 by the driving force of the charcoal feeder motor 27, and inputs it inside. The amount of solid fuel supplied to the mill 10 is controlled by a signal from the control section 50, for example, by adjusting the moving speed of the belt conveyor of the conveying section 26.

Normally, primary air is supplied to the inside of the mill 10 to transport pulverized fuel to the burner 220, and the pressure is higher than that of the coal feeder 25 and the bunker 21. Inside the downspout section 22 that connects the bunker 21 and the coal feeder 25, the fuel is layered. This solid fuel layer ensures a sealing property (material seal) to prevent the primary air and pulverized fuel from flowing back from the mill 10 toward the bunker 21.

The blower section 30 is a device that blows primary air into the housing 11 to dry the pulverized fuel and to transport the fuel to the rotary classifier 16 .
In order to appropriately adjust the flow rate and temperature of the primary air blown into the housing 11, in this embodiment, the blower 30 includes 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 this embodiment, the hot gas flow path 30a supplies a portion of the air sent out from the primary air ventilator 31 as hot gas that has been heated by passing through an air preheater (heat exchanger) 34. A hot gas damper 30c is provided in 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 portion of the air sent out from the primary air ventilator 31 as cold gas at room temperature. A cold gas damper 30d is provided in 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 this embodiment, 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.
Furthermore, the oxygen concentration in the primary air blown from the primary air passage 110 to the inside of the housing 11 may be adjusted by, for example, introducing a part of the combustion gas discharged from the boiler 200 by a gas recirculation fan (not shown) into the hot gas supplied from the hot gas passage 30a and mixing it. By adjusting the oxygen concentration in the primary air, for example, when a solid fuel with high ignition properties (easy to ignite) is used, the ignition of the solid fuel in the path from the mill 10 to the burner 220 can be suppressed.

In this embodiment, data measured or detected by the state detection unit 40 of the mill 10 is transmitted to the control unit 50. The state detection unit 40 of this embodiment is, for example, a differential pressure measurement means, and measures the differential pressure of the mill 10 as the pressure difference between the pressure at the portion where the primary air flows into the inside of the housing 11 from the primary air flow passage 110 and the pressure at the outlet port 19 where the primary air and the pulverized fuel are discharged from the inside of the housing 11 to the pulverized fuel supply pipe 120. 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 in accordance with the pressure difference across the mill 10, the amount and particle size range of the pulverized fuel discharged from the outlet port 19 can be adjusted, so that 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, while maintaining the particle size of the pulverized fuel within a range that does not affect the combustibility of the solid fuel in the burner 220.
The state detection unit 40 of this embodiment is, for example, a temperature measuring means, which detects the temperature of the primary air supplied to the inside of the housing 11 (mill inlet primary air temperature) and the temperature of the mixed gas of the primary air and the pulverized fuel at the outlet port 19 (mill outlet primary air temperature), and controls the blower unit 30 so that the respective upper limit temperatures are not exceeded. Each upper limit temperature is determined in consideration of the possibility of ignition according to the properties of the solid fuel. Note that, since the primary air is cooled inside the housing 11 by transporting the pulverized fuel while drying it, the primary air temperature at the mill inlet is, for example, about room temperature to about 300°C, and the primary air temperature at the mill outlet is, for example, about room temperature to about 90°C.

The control unit 50 is a device that controls each part of the solid fuel pulverization device 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 to adjust the classification performance, and can stably supply an amount of pulverized fuel corresponding to the amount of solid fuel supplied to the mill 10 to the burner 220 while maintaining the particle size of the pulverized fuel within a range that does not affect the combustibility of the solid fuel in the burner 220.
In addition, the control unit 50 can adjust the amount of solid fuel supplied (amount of coal supplied) to the mill 10 by, for example, transmitting a drive command to the coal feeder motor 27 .
Moreover, 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 unit 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 (mill outlet primary air temperature) become predetermined values set corresponding to the coal feed amount for each type of solid fuel. The temperature of the primary air may be controlled with respect to the temperature at the mill inlet (mill inlet primary air temperature).

The control unit 50 is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium in the form of a program, for example, and the CPU reads this program into the RAM and executes information processing and arithmetic processing to realize 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 also be replaced with a solid-state disk (SSD), etc.

Next, we will explain the boiler 200 that generates steam by burning pulverized fuel supplied from the solid fuel pulverizer 100. The boiler 200 is equipped with a furnace 210 and a burner 220.

The burner 220 is a device that burns pulverized fuel to form a flame using a mixture of pulverized fuel and primary air supplied from the pulverized fuel supply pipe 120 and secondary air supplied by heating the air (outside air) sent out from the forced draft fan (FDF: Forced Draft Fan) 32 in an air preheater 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.

The combustion gas discharged from the boiler 200 undergoes predetermined treatment in an environmental device (such as a denitration device, dust collector, and desulfurization device, not shown), and is then heat-exchanged with primary air and secondary air in an air preheater 34, and is then guided to a chimney (not shown) via an induced draft fan (IDF) 33 and released into the outside air. The air heated by the combustion gas in the air preheater 34 and discharged from the primary air fan 31 is supplied to the above-mentioned hot gas flow path 30a.
The water supplied to each heat exchanger of boiler 200 is heated in a coal economizer (not shown), and then further heated by an evaporator (not shown) and a superheater (not shown) to generate high-temperature, high-pressure superheated steam. This is then sent to the steam turbine (not shown), which is the power generation section, to rotate the steam turbine, which in turn rotates a generator (not shown) connected to the steam turbine to generate electricity, thereby constituting power generation plant 1.

Next, the details of the crushing roller 13 and the crushing table 12 according to this embodiment will be described in detail with reference to FIGS.
As shown in Figs. 1 and 2, each of the crushing rollers 13 is supported by the housing 11 via a journal shaft 44, a journal head 45, and a support shaft 48 so as to be rotatable about the rotation center axis C2. The journal shaft 44 extends from the vicinity of the side portion of the housing 11 to the central portion of the housing 11 so as to be inclined downward. The journal shaft 44 has a base end (an end portion on the side portion side of the housing 11) fixed to the journal head 45. The crushing roller 13 is rotatably supported by a tip end (an end portion on the central portion side of the mill 10) of the journal shaft 44 via a bearing (not shown). That is, the crushing roller 13 is rotatably supported vertically above the crushing table 12 in an inclined state in which the upper side faces the central portion of the housing 11 more than the lower side.

As shown in FIG. 2, the crushing roller 13 includes a journal housing (support portion) 43 that is supported at the tip of the journal shaft 44 so as to be rotatable about the central axis of rotation C2, and a substantially annular roller portion 49 that is fitted onto the journal housing 43. The journal housing 43 is provided to cover the tip of the journal shaft 44, and has a cylindrical outer circumferential surface.

3 and 4 show a main part of a cross section of the roller portion 49 taken along a plane including the direction in which the rotational center axis C2 of the roller portion 49 extends (hereinafter referred to as an "axial cross section").
3 and 4, the roller portion 49 includes a base portion 51 made of high chromium cast iron that fits into the journal housing 43, and a ceramic portion 52 that includes a ceramic member provided on an outer circumferential surface 51a of the base portion 51. In other words, the roller portion 49 according to this embodiment is a so-called ceramic-embedded high chromium cast iron roller.
The roller portion 49 has an outer peripheral surface 49a that is substantially annular, and an inner peripheral surface (the surface that comes into contact with the outer peripheral surface of the journal housing 43) that is substantially cylindrical. The outer peripheral surface 49a and the inner peripheral surface of the roller portion 49 are connected at end faces. The outer peripheral surface 49a of the roller portion 49 is curved so as to form an arc shape centered on a center point CP in an axial cross section. The inner peripheral surface of the roller portion 49 is a straight line parallel to the central rotation axis C2 in an axial cross section.

The base 51 is supported by the journal housing 43. The base 51 is formed in a substantially annular shape. The base 51 is fitted to the journal housing 43 so that the inner peripheral surface of the base 51 contacts the outer peripheral surface of the journal housing 43. The ceramic part 52 is fixed to the outer peripheral part of the annular base 51. The ceramic part 52 is provided over substantially the entire circumferential area of the base 51. That is, the ceramic part 52 is formed in a substantially annular shape. The ceramic part 52 does not cover the entire outer peripheral surface 51a of the base 51, but covers the base end side of the roller part 49 of the outer peripheral surface 51a of the base 51. Here, the base end side is the journal shaft 44 side to which the grinding roller 13 is connected, and indicates the outer peripheral side in the radial direction of the grinding table 12, and the tip side indicates the rotation center axis C1 (see FIG. 1) side in the radial direction of the grinding table 12. That is, the outer peripheral surface 49a of the roller portion 49 (the surface that crushes the solid fuel) is formed by the outer peripheral surface 52a of the ceramic portion 52 on the base end side, and by the outer peripheral surface 51a of the base portion 51 on the tip end side (the side opposite the base end side).

Since the ceramic portion 52 contains ceramic members (such as the first ceramic particles 52c), it has a smaller linear expansion coefficient than the base portion 51 made of high chromium cast iron. In addition, the ceramic portion 52 has better wear resistance than the base portion 51. The material of the base portion 51 is not limited to the materials described above.

The dashed line L1 in FIG. 2 shows the progression of wear of the roller portion 49 as a result of a general mill 10 (in other words, a mill not applying the grinding roller 13 or grinding table 12 according to the present disclosure) grinding solid fuel. That is, the roller portion 49 is in a state where a portion P1 (hereinafter referred to as the "maximum wear point P1") on the base end side (i.e., the side opposite to the tip side) of the roller portion 49 is worn more than other portions. As described above, the base end side refers to the outer periphery side in the radial direction of the grinding table 12, and the tip side refers to the side of the rotation center axis C1 (see FIG. 1) of the grinding table 12. The dashed line L2 in FIG. 2 shows the progression of wear of the grinding table 12. The table portion 12a of the grinding table 12 (see FIG. 8) is in a state where a portion P2 (hereinafter referred to as the "maximum wear point P2") is worn more than other portions.
In Fig. 2, the maximum wear points before wear are indicated by the symbols "P1" and "P2," and the maximum wear points after wear has actually progressed are indicated by the symbols "P1'" and "P2'." The maximum wear points P1 and P2 before wear are the points at which wear is expected to progress most easily if no measures against wear are taken.

As shown in Figures 3 and 4, the maximum wear point P1 is a position on the outer circumferential surface 49a of the roller part 49 that forms a predetermined angle θ1 on the base end side at the center point CP with respect to a center line C3 that is a line that is perpendicular to the rotation central axis C2 and passes through the center in the direction in which the rotation central axis C2 extends. More specifically, it is a position where a line L3 that forms a predetermined angle θ1 with the center line C3 intersects with the outer circumferential surface 49a. In this embodiment, the angle θ1 is set to 8 degrees as an example, but the angle θ1 is not limited to 8 degrees. The angle θ1 may be within the range of 3 degrees to 13 degrees (a range of 8 degrees plus or minus 5 degrees).
In this embodiment, the thickness of the ceramic portion 52 in the axial cross section is greatest at a portion where a line L3 that forms a predetermined angle θ1 with the center line C3 passes.

Next, the ceramic portion 52 will be described in detail with reference to FIGS.
Fig. 3 shows the ceramic part 52 according to this embodiment, and Fig. 4 shows a ceramic part 52A according to a modified example of this embodiment.

3, the ceramic part 52 according to the present embodiment includes a metallic base material 52b and a large number of first ceramic particles 52c and second ceramic particles 52d contained in the base material 52b. The large number of first ceramic particles 52c and second ceramic particles 52d are dispersed in the base material 52b and bonded to adjacent ceramic particles. The particle diameters of the first ceramic particles 52c and second ceramic particles 52d are, for example, about 1 mm to 2 mm.
The first ceramic particles 52c and the second ceramic particles 52d have different rigidity and toughness.
The first ceramic particles 52c are ceramic particles having high rigidity and excellent wear resistance. The first ceramic particles 52c are more rigid and more wear resistant than the second ceramic particles 52d. The first ceramic particles 52c are less tough than the second ceramic particles 52d. The first ceramic particles 52c are made of, for example, alumina.
The second ceramic particles 52d are ceramic particles having high toughness. The second ceramic particles 52d have higher toughness than the first ceramic particles 52c. The second ceramic particles 52d have lower rigidity than the first ceramic particles 52c. The second ceramic particles 52d are made of, for example, zirconia oxide.
The materials forming the first ceramic particles 52c and the second ceramic particles 52d are not limited to the above materials. The first ceramic particles 52c and the second ceramic particles 52d may be other materials as long as they have different rigidity and toughness. The first ceramic particles 52c and the second ceramic particles 52d may each be made of a single material, and the rigidity and toughness may be different by making the material different. The first ceramic particles 52c and the second ceramic particles 52d may also have different rigidity and toughness by making the combination of multiple materials different. Examples of materials to be combined include alumina, zirconia, yttria, etc.

3, the first ceramic particles 52c and the second ceramic particles 52d are mixed in the ceramic portion 52. The mixture ratio of the first ceramic particles 52c and the second ceramic particles 52d includes a case where either of the ceramic particles is 100%. That is, the ceramic portion 52 may have a portion where only the first ceramic particles 52c are present, or a portion where only the second ceramic particles 52d are present.
In the ceramic part 52, the mixing ratio of the first ceramic particles 52c and the second ceramic particles 52d changes along the direction of the rotation axis C2 (left-right direction on the paper). Specifically, in the ceramic part 52, the mixing ratio of the first ceramic particles 52c in a region (first region) including the maximum wear point P1, which is the most easily worn point on the outer circumferential surface 49a of the roller part 49, is higher than the mixing ratio of the first ceramic particles 52c in other regions (second regions). In detail, in the ceramic part 52, the mixing ratio of the first ceramic particles 52c decreases continuously as it moves away from the maximum wear point P1 (specifically, the line L3 passing through the maximum wear point P1 and the center point CP) in the direction of the rotation axis C2.
It is preferable that the ceramic density of the ceramic portion 52 be uniform in the circumferential direction of the roller portion 49 .
In addition, it is preferable that the mixing ratio of the first ceramic particles 52c is set to a slope of at least 0.5 of the wear resistance required for each portion.

As shown in Fig. 4, the ceramic part 52A according to the modified embodiment of the present invention has a high mixture part 52Aa having a high mixture ratio of the first ceramic particles 52c, two medium mixture parts 52Ab arranged adjacent to both sides of the high mixture part 52Aa in the direction of the rotation axis C2 and having a lower mixture ratio of the first ceramic particles 52c than the high mixture part 52Aa, and two low mixture parts 52Ac arranged adjacent to the opposite side of the high mixture part 52Aa in the direction of the rotation axis C2 of each medium mixture part 52Ab and having a lower mixture ratio of the first ceramic particles 52c than the medium mixture part 52Ab. The ceramic part 52A has a stepwise (three steps in this embodiment as an example) lower mixture ratio of the first ceramic particles 52c as it moves away from the maximum wear point P1 in the direction of the rotation axis C2.
The high mixture portion 52Aa, the medium mixture portion 52Ab, and the low mixture portion 52Ac are connected by bonding between the base materials contained in each portion. The high mixture portion 52Aa, the medium mixture portion 52Ab, and the low mixture portion 52Ac are each provided over the entire circumferential area of the roller portion 49.
The high mixture portion 52Aa, the medium mixture portion 52Ab, and the low mixture portion 52Ac are each formed so as to have a uniform mixture ratio.
In this modification, as an example, the mixture ratio of the first ceramic particles 52c and the second ceramic particles 52d in the high mixture portion 52Aa is 100% first ceramic particles 52c. In other words, the high mixture portion 52Aa does not contain the second ceramic particles 52d. The high mixture portion 52Aa is formed only of the base material 52b and the first ceramic particles 52c.
Also, for example, the mixture ratio of the first ceramic particles 52c and the second ceramic particles 52d in the intermediate mixture portion 52Ab is 50% first ceramic particles 52c and 50% second ceramic particles 52d.
In addition, for example, the mixture ratio of the first ceramic particles 52c and the second ceramic particles 52d in the low mixture portion 52Ac is set to 0% for the first ceramic particles 52c. In other words, the low mixture portion 52Ac does not contain the first ceramic particles 52c. The low mixture portion 52Ac is formed only of the base material 52b and the second ceramic particles 52d.

As shown in FIG. 4, by arranging the high mixture portion 52Aa, the medium mixture portion 52Ab, and the low mixture portion 52Ac side by side in the ceramic portion 52A, the high mixture portion 52Aa, the medium mixture portion 52Ab, and the low mixture portion 52Ac, which have different mixture ratios of the first ceramic particles 52c and the second ceramic particles 52d, can be manufactured, and by simply arranging the high mixture portion 52Aa, the medium mixture portion 52Ab, and the low mixture portion 52Ac side by side in the rotation axis direction, the ceramic portion 52A in which the mixture ratio of the first ceramic particles 52c and the second ceramic particles 52d is changed in the rotation axis direction of the ceramic portion 52A can be easily manufactured.

The high mixing section 52Aa is positioned so as to include the maximum wear point P1. More specifically, the high mixing section 52Aa is positioned so that the maximum wear point P1 overlaps with the middle of the high mixing section 52Aa in the direction of the rotation center axis C2. The two medium mixing sections 52Ab are positioned so as to sandwich the high mixing section 52Aa in the direction of the rotation center axis C2. Each medium mixing section 52Ab is positioned so as to be sandwiched between the high mixing section 52Aa and the low mixing section 52Ac. The two low mixing sections 52Ac are positioned so as to sandwich the medium mixing section 52Ab in the direction of the rotation center axis C2. Each low mixing section 52Ac is positioned at both ends of the ceramic section 52A in the direction of the rotation center axis C2.

In the above description, the high mixture portion 52Aa, the medium mixture portion 52Ab, and the low mixture portion 52Ac are provided over the entire circumferential area of the roller portion 49, but the present disclosure is not limited thereto. For example, as shown in FIG. 6 and FIG. 7, the high mixture portion 52Aa and the low mixture portion 52Ac may be arranged alternately in the circumferential direction of the roller portion 49 to substitute for the medium mixture portion 52Ab. In this way, the number of manufactured parts having different mixture ratios of the first ceramic particles 52c and the second ceramic particles 52d can be reduced, and the manufacture of the ceramic portion 52A can be facilitated. In addition, by arranging the ceramic portions having different mixture ratios of the first ceramic particles 52c and the second ceramic particles 52d in the circumferential direction of the roller portion 49, unevenness is formed in the circumferential direction of the roller surface due to the difference in the amount of wear. This unevenness promotes the biting of the solid fuel, which is the object to be crushed, and therefore the slippage of the crushing roller 13 can be suppressed.
6 and 7 are enlarged views of a main portion (part VI) of the outer circumferential surface 49a of the roller portion 49 shown in Fig. 5. The arrows in Fig. 6 and 7 indicate the rotation direction of the roller portion 49. In Fig. 6 and 7, the region where only the high mixture portion 52Aa is arranged is indicated as (1), the region where only the low mixture portion 52Ac is arranged is indicated as (2), and the region where the high mixture portion 52Aa and the low mixture portion 52Ac are arranged is indicated as (1)+(2).

As shown in FIG. 6, the high-mixed portion 52Aa arranged in the region where the high-mixed portion 52Aa and the low-mixed portion 52Ac are arranged may be provided separately from the high-mixed portion 52Aa arranged in the region where only the high-mixed portion 52Aa is arranged. In this case, as shown in FIG. 6, the high-mixed portion 52Aa arranged in the region where the high-mixed portion 52Aa and the low-mixed portion 52Ac are arranged and the high-mixed portion 52Aa arranged in the region where only the high-mixed portion 52Aa is arranged may be arranged to be shifted in the circumferential direction. Similarly, the low-mixed portion 52Ac arranged in the region where the high-mixed portion 52Aa and the low-mixed portion 52Ac are arranged may be provided separately from the low-mixed portion 52Ac arranged in the region where only the low-mixed portion 52Ac is arranged. In this case, the low-mixed portion 52Ac arranged in the region where the high-mixed portion 52Aa and the low-mixed portion 52Ac are arranged and the low-mixed portion 52Ac arranged in the region where only the low-mixed portion 52Ac is arranged may be arranged to be shifted in the circumferential direction.
Moreover, each of the high-mixture portions 52Aa and the low-mixture portions 52Ac is formed in a rectangular shape in a plan view. By forming the high-mixture portions 52Aa and the low-mixture portions 52Ac in this manner with a relatively simple shape, the high-mixture portions 52Aa and the low-mixture portions 52Ac can be easily manufactured.

Also, as shown in Fig. 7, the high mixing portion 52Aa arranged in the region where the high mixing portion 52Aa and the low mixing portion 52Ac are arranged may be provided integrally with the high mixing portion 52Aa arranged in the region where only the high mixing portion 52Aa is arranged. In this case, as shown in Fig. 7, the high mixing portion 52Aa and the low mixing portion 52Ac are arranged to be shifted in the circumferential direction. Also, both ends of the high mixing portion 52Aa in the direction of the rotation center axis C2 (left and right direction of the paper) are arranged in the region where the high mixing portion 52Aa and the low mixing portion 52Ac are arranged. The part of the high mixing portion 52Aa arranged in the region where the high mixing portion 52Aa and the low mixing portion 52Ac are arranged is formed so that the circumferential length becomes shorter toward the end in the direction of the rotation center axis C2.
The end of the low mixing section 52Ac on the central side in the direction of the rotation axis C2 (left-right direction on the paper) is disposed in the region where the high mixing section 52Aa and the low mixing section 52Ac are disposed. The portion of the low mixing section 52Ac that is disposed in the region where the high mixing section 52Aa and the low mixing section 52Ac are disposed is formed so that its circumferential length becomes shorter toward the center in the direction of the rotation axis C2.
In the example of FIG. 7, in a region where the high-mixture portions 52Aa and the low-mixture portions 52Ac are arranged, the tapered high-mixture portions 52Aa and the low-mixture portions 52Ac are arranged alternately so as to mesh with each other.

Next, the grinding table 12 will be described with reference to FIGS.
As shown in Fig. 1, solid fuel is supplied to the grinding table 12 from a coal supply pipe 17 (see Fig. 1). The grinding table 12 rotates about a central rotation axis C1 by a driving force transmitted from a mill motor 15. Also, as shown in Fig. 8, the grinding table 12 includes a table portion 12a to which solid fuel is supplied and a support portion 12b that supports the table portion 12a from below.

The table portion 12a has a base portion 12c supported by the support portion 12b, and a ceramic portion 12d provided on the upper surface of the base portion 12c, which has a linear expansion coefficient different from that of the base portion 12c and is more wear-resistant than the base portion 12c.
The solid fuel is supplied to the upper surface of the ceramic portion 12d. The ceramic portion 12d is formed over substantially the entire circumferential area of the table portion 12a. That is, the ceramic portion 12d has a circular ring shape when viewed from above.

The ceramic part 12d has a metallic base material and a large number of first ceramic particles 52c and second ceramic particles 52d contained in the base material. The large number of first ceramic particles 52c and second ceramic particles 52d are scattered in the base material and bonded to adjacent ceramic particles. The particle size of the ceramic particles is, for example, about 1 mm to 2 mm. Note that in Figures 8 and 9, the first ceramic particles 52c and second ceramic particles 52d are omitted from the illustration.

9, the ceramic part 12d has a mixing ratio of the first ceramic particles 52c and the second ceramic particles 52d that changes along the radial direction (left-right direction on the paper) of the table part 12a. Specifically, the ceramic part 12d has a higher mixing ratio of the first ceramic particles 52c in the region (first region) including the maximum wear point P2, which is the most easily worn point on the upper surface of the table part 12a, than in the other region (second region). In detail, the ceramic part 12d has a lower mixing ratio of the first ceramic particles 52c as it moves away from the maximum wear point P2 in the radial direction of the table part 12a. The maximum wear point P2 of the table part 12a is located radially toward the center side of the center line C3 of the grinding roller 13.

The ceramic portion 12d has a high mixture portion 12da having a high mixture ratio of the first ceramic particles 52c, two medium mixture portions 12db arranged adjacent to both sides of the high mixture portion 12da in the radial direction and having a lower mixture ratio of the first ceramic particles 52c than the high mixture portion 12da, and two low mixture portions 12dc arranged adjacent to the opposite side of the high mixture portion 12da in the radial direction of each medium mixture portion 12db and having a lower mixture ratio of the first ceramic particles 52c than the medium mixture portion 12db. The ceramic portion 12d has a stepwise (three steps in this embodiment as an example) lower mixture ratio of the first ceramic particles 52c as it moves away from the maximum wear point P2 in the radial direction of the table portion 12a.
The high mixture portion 12da, the medium mixture portion 12db, and the low mixture portion 12dc are connected to each other by bonding between the base materials contained in each portion. The high mixture portion 12da, the medium mixture portion 12db, and the low mixture portion 12dc are each provided over the entire circumferential area of the table portion 12a.

The high mixing section 12da is positioned so as to include the maximum wear point P2. More specifically, the high mixing section 12da is positioned so that the maximum wear point P2 overlaps with approximately the center in the radial direction. The two medium mixing sections 12db are positioned so as to sandwich the high mixing section 12da in the radial direction. Each medium mixing section 12db is positioned so as to be sandwiched between the high mixing section 12da and the low mixing section 12dc. The two low mixing sections 12dc are positioned so as to sandwich the medium mixing section 12db in the radial direction. Each low mixing section 12dc is positioned at both radial ends of the ceramic section 12d.

Next, a method for manufacturing the roller portion 49 will be described with reference to Figures 10 to 12. UP in Figures 10 to 12 indicates the upward vertical direction.

First, a method for manufacturing the roller portion 49 having the ceramic portion 52 in which the ceramic density changes continuously as shown in FIG. 3 will be described with reference to FIG.
First, ceramic particles (first ceramic particles 52c and second ceramic particles 52d) are shaped into a block shape (a shape corresponding to the ceramic portion 52) to manufacture a ceramic block CB that constitutes a part of the ceramic portion 52. The ceramic block CB is made by bonding particulate ceramics, and a relatively large number of gaps are formed between the ceramic particles (first ceramic particles 52c and second ceramic particles 52d). The shape of the outer circumferential surface of the ceramic block CB is substantially the same as the shape of the outer circumferential surface 52a of the ceramic portion 52 (see Figures 3 and 4, etc.).
The ceramic block CB is manufactured to correspond to the ceramic part 52 to be provided in the roller part 49 to be manufactured. Therefore, in the example of Fig. 10, the ceramic block CB is manufactured so that the mixing ratio of the first ceramic particles 52c continuously decreases with increasing distance from the maximum wear point P1 (see Fig. 3, etc.) in the direction of the central axis of rotation C2.

Next, the manufactured ceramic block CB is placed at a predetermined position in the mold 60. Next, molten metal is poured into the mold 60 from the sprue 61 through the runner 62. As a result, the mold 60 is filled with the molten metal (see arrow m). At this time, since the ceramic block CB has a lower specific gravity than the molten metal, it is pressed against a predetermined position on the inner circumferential surface of the mold 60 by buoyancy. In detail, as shown in FIG. 10, the upper surface CBa of the ceramic block CB (the surface corresponding to the end surface on the base end side of the ceramic part 52) is pressed against the ceiling surface of the mold 60, and the ceramic block CB is supported by this upper surface CBa on the mold 60. At this time, the molten metal also flows into the gaps formed between the ceramic particles (the first ceramic particles 52c and the second ceramic particles 52d) inside the ceramic block CB. As a result, the ceramic part 52 is provided so that the first ceramic particles 52c and the second ceramic particles 52d are scattered.

Next, the molten metal is cooled and solidified, thereby completing the roller part 49 in which the ceramic part 52 having excellent abrasion resistance, in which the metal has entered between the ceramic particles (the first ceramic particles 52c and the second ceramic particles 52d) inside the ceramic block CB, and the base part 51 made only of the solidified metal are integrated together.
In the ceramic portion 52 , the metal flows into the gaps between the bonded ceramic particles (the first ceramic particles 52 c and the second ceramic particles 52 d ) and solidifies to become the base material 52 b of the ceramic portion 52 .
In this manner, the roller portion 49 of the present embodiment is manufactured by insert-casting the base portion 51 and the ceramic portion 52 together.

Next, a method for manufacturing the roller portion 49 having the ceramic portion 52A shown in FIG. 4 will be described with reference to FIG.
When manufacturing the ceramic portion 52A, ceramic blocks corresponding to the high mixture portion 52Aa, the medium mixture portion 52Ab, and the low mixture portion 52Ac are manufactured. Next, a high mixture block CBAa corresponding to the high mixture portion 52Aa, a medium mixture block CBAb corresponding to the medium mixture portion 52Ab, and a low mixture block CBAc corresponding to the low mixture portion 52Ac are fixed with a fixing member 53 to manufacture one ceramic block CBA. At this time, slight gaps may be present between the ceramic blocks.

Next, the manufactured ceramic block CBA is placed at a predetermined position in the mold 60. That is, the ceramic block CBA is placed at a predetermined position in the mold 60 in a state in which the high mixture block CBAa corresponding to the high mixture portion 52Aa, the medium mixture block CBAb corresponding to the medium mixture portion 52Ab, and the low mixture block CBAc corresponding to the low mixture portion 52Ac are fixed (ceramic portion placement process).
The subsequent steps are the same as those in the manufacturing method for the roller portion 49 having the ceramic portion 52 described above, and therefore the description thereof will be omitted.

By manufacturing in this manner, the ceramic block CBA can be arranged with the relative positions of the high mixing block CBAa corresponding to the high mixing portion 52Aa, the medium mixing block CBAb corresponding to the medium mixing portion 52Ab, and the low mixing block CBAc corresponding to the low mixing portion 52Ac determined, so that the ceramic block CBA can be arranged easily. Therefore, the ceramic portion 52A having the high mixing portion 52Aa, the medium mixing portion 52Ab, and the low mixing portion 52Ac can be easily manufactured.

The ceramic portion 52A shown in FIG. 4 may be manufactured as follows, which will be described with reference to FIG.
First, a high mixing block CBAa corresponding to the high mixing section 52Aa, a medium mixing block CBAb corresponding to the medium mixing section 52Ab, and a low mixing block CBAc corresponding to the low mixing section 52Ac are manufactured. At this time, a high mixing section fixing section FAa protruding from the outer circumferential surface is provided in the high mixing block CBAa. Similarly, a medium mixing section fixing section FAb protruding from the outer circumferential surface is provided in the medium mixing block CBAb. Similarly, a low mixing section fixing section FAc protruding from the outer circumferential surface is provided in the low mixing block CBAc.

Next, the manufactured high-mixed block CBAa, medium-mixed block CBAb, and low-mixed block CBAc are placed at predetermined positions in the mold 60. In the mold 60, a high-mixed recess that fits with the high-mixed section fixing section FAa, a medium-mixed recess that fits with the medium-mixed block CBAb, and a low-mixed recess that fits with the low-mixed block CBAc are formed at predetermined positions. When placing each block in the mold 60, the high-mixed section fixing section FAa is fitted into the high-mixed recess, the medium-mixed block CBAb is fitted into the medium-mixed recess, and the low-mixed block CBAc is fitted into the low-mixed recess. As a result, the high-mixed block CBAa, the medium-mixed block CBAb, and the low-mixed block CBAc are positioned at their respective predetermined positions (high-mixed section fixing process, low-mixed section (medium-mixed section) fixing process).
The subsequent steps are the same as those in the manufacturing method of the roller part 49 including the ceramic part 52 described above, and therefore will not be described. However, in this modification, the high mixture part fixing part FAa, the medium mixture part fixing part FAb, and the low mixture part fixing part FAc are removed from the roller part 49 removed from the mold 60.

The ceramic block CB shown in FIG. 10 may be fixed to the mold 60 by the method shown in FIG. 12. That is, a fixing portion may be provided on the ceramic block CB, and a recess may be provided on the mold 60 to fit the fixing portion, and the ceramic block CB may be fixed at a predetermined position in the mold 60 by fitting the fixing portion into the recess.

By manufacturing in this manner, the high mixing block CBAa corresponding to the high mixing portion 52Aa, the medium mixing block CBAb corresponding to the medium mixing portion 52Ab, and the low mixing block CBAc corresponding to the low mixing portion 52Ac can be easily fixed to predetermined locations in the mold 60. Therefore, the ceramic portion 52A having the high mixing portion 52Aa, the medium mixing portion 52Ab, and the low mixing portion 52Ac can be easily manufactured.

According to this embodiment, the following advantageous effects are obtained.
In the present embodiment, the mixture ratio of the first ceramic particles 52c and the second ceramic particles 52d changes along the rotation axis direction of the ceramic portion 52. This makes it possible to change the rigidity of the ceramic portion 52 along the rotation axis direction.

In addition, in this embodiment, the mixing ratio of the first ceramic particles 52c in the region including the maximum wear point P1 is higher than the mixing ratio of the first ceramic particles 52c in other regions. This improves the rigidity and wear resistance of the region including the maximum wear point P1. This improves the wear resistance of the grinding roller 13. This prevents the life of the grinding roller 13 from being shortened, and extends the life of the grinding roller 13.
On the other hand, since the mixing ratio of the first ceramic particles 52c in the other regions is low, the rigidity of the ceramic part 52 as a whole can be reduced and the toughness can be increased, compared to the case where the mixing ratio of the first ceramic particles 52c in all regions is high. Therefore, the ceramic part 52 can easily absorb the thermal stress between the base part 51 and the ceramic part 52, so that damage to the ceramic part 52 caused by the difference in linear expansion coefficient can be suppressed. Therefore, the yield rate when manufacturing the crushing roller 13 can be improved, and the manufacturing cost can be reduced.
In this manner, in this embodiment, the yield rate in manufacturing the crushing roller 13 can be improved, and the life of the crushing roller 13 can be extended.
In addition, since damage during casting can be suppressed even if the ceramic portion 52 is made thick, the thickness of the ceramic portion 52 can be increased compared to the conventional case, and the life of the crushing roller 13 can be further extended.

2, when a part of the surface of the crushing roller 13 is locally worn, the engagement with the table portion 12a of the crushing table 12 may become poor, and the crushing performance may decrease. Specifically, when a depression is formed on the surface of the crushing roller 13, the solid fuel that should be sandwiched between the crushing roller 13 and the table portion 12a and crushed can pass through the crushing roller 13 without being crushed, and the crushing efficiency decreases. In particular, when the most efficient part of the surface of the crushing roller 13 (maximum wear point P1) becomes depressed due to wear and the crushing performance decreases, the crushing is performed in the part around the maximum wear point P1 with low crushing efficiency, and the overall crushing performance of the mill 10 gradually decreases.
On the other hand, in this embodiment, the mixing ratio of the first ceramic particles 52c in the region including the maximum wear point P1 is higher than the mixing ratio of the first ceramic particles 52c in the other regions. Therefore, as shown by the dashed line in FIG. 13, wear is suppressed in the region that is easily worn including the maximum wear point P1, and wear is relatively easy to progress in the other regions. This makes the amount of wear uniform between the region including the maximum wear point P1 and the other regions. Therefore, as shown by the dashed line in FIG. 13, it is possible to suppress local wear of the outer surface of the ceramic part 52. Therefore, it is possible to suppress the deterioration of the meshing between the grinding roller 13 and the grinding table 12, and therefore it is possible to suppress the deterioration of the grinding performance.
In addition, as the grinding roller 13 wears, the gap between the grinding roller 13 and the grinding table 12 increases. When this gap becomes large, the gap is reduced by using a gap bolt (not shown) that can adjust the length of the gap.

Furthermore, when attaching the roller portion 49 to the journal housing 43, the roller portion 49 may be heated and shrink-fitted into the journal housing 43. At this time, thermal stress is generated inside the roller portion 49, but in this embodiment, as described above, the ceramic portion 52 can easily absorb the thermal stress between the base portion 51 and the ceramic portion 52, so that damage to the ceramic portion 52 caused by the difference in linear expansion coefficient can be suppressed.
Furthermore, when removing the roller portion 49 from the journal housing 43, the roller portion 49 may be heated to facilitate removal. In this case, thermal stress is also generated inside the roller portion 49, but in this embodiment, the ceramic portion 52 can easily absorb the thermal stress between the base portion 51 and the ceramic portion 52 as described above, so that damage to the ceramic portion 52 caused by the difference in linear expansion coefficient can be suppressed.
In this manner, in this embodiment, the roller portion 49 can be easily handled when being attached or replaced.

In this embodiment, the mixture ratio of the first ceramic particles 52c and the second ceramic particles 52d changes along the radial direction of the table portion 12a in the ceramic portion 12d of the grinding table 12. This allows the rigidity of the ceramic portion 12d to be changed along the radial direction of the table portion 12a.
In addition, in this embodiment, the mixing ratio of the first ceramic particles 52c in the region including the maximum wear point P2 of the grinding table 12 is higher than the mixing ratio of the first ceramic particles 52c in other regions. This makes it possible to improve the rigidity and wear resistance of the region including the maximum wear point P2. Therefore, it is possible to improve the wear resistance of the grinding table 12. This makes it possible to prevent the life of the grinding table 12 from being shortened, and to extend the life of the grinding table 12.
On the other hand, since the mixing ratio of the first ceramic particles 52c in the other regions is low, the rigidity of the ceramic part 12d as a whole can be reduced and the toughness can be increased, compared to the case where the mixing ratio of the first ceramic particles 52c in all regions is high. Therefore, the ceramic part 12d can easily absorb the thermal stress between the base 12c and the ceramic part 12d, so that damage to the ceramic part 12d caused by the difference in linear expansion coefficient can be suppressed. Therefore, the yield rate when manufacturing the grinding table 12 can be improved, and the manufacturing cost can be reduced.
In this way, in this embodiment, the yield rate when manufacturing the rotary table 12 can be improved, and the service life of the rotary table 12 can be extended.

[Second embodiment]
Next, a second embodiment of the present disclosure will be described with reference to FIGS.
In the mill 10, as the wear of the roller portion 49 progresses, the roller portion 49 may be reversed for use. That is, the roller portion 49 may be removed from the journal housing 43, the base end side and the tip end side may be swapped, and the roller portion 49 may be reattached to the journal housing 43 for use. In this case, the maximum wear point is a position symmetrical with respect to the center line C3. In detail, as shown in FIG. 14, it is a point P3 where the outer peripheral surface 49a of the roller portion 49 intersects with a line L4 that is symmetrical with a line L3 that forms a predetermined angle θ1 with the center line C3.

14, in the ceramic part 152 according to this embodiment, the mixture ratio of the first ceramic particles 52c in region A between point P3 and maximum wear point P1 in the direction of the rotation center axis C2 (left-right direction on the page) is higher than the mixture ratio of the first ceramic particles 52c in other regions. That is, region A has the highest mixture ratio of the first ceramic particles 52c. Region A includes maximum wear point P1 and point P3. Since the second embodiment is otherwise similar to the first embodiment, the same reference numerals are used for similar configurations and detailed description thereof will be omitted.
In this way, even when the roller portion 49 is used in an inverted manner, the mixing ratio of the first ceramic particles 52c in the region that is easily worn can be increased, and the life of the crushing roller 13 can be further extended.

15, the mixing ratio of the first ceramic particles 52c in the region (third region) B including the point P3 and in the vicinity of the maximum wear point P3 and the region (first region) C including the maximum wear point P1 and in the vicinity of the maximum wear point P1 may be made higher than the mixing ratio of the first ceramic particles 52c in the other regions (second regions). That is, the mixing ratio of the first ceramic particles 52c in the regions B and C is the highest.
By doing this, even when the roller portion 49 is used inverted, the mixing ratio of the first ceramic particles 52c in the area prone to wear can be increased, thereby further extending the life of the crushing roller 13.

The required wear resistance of the ceramic part 152 differs at each position in the direction of the central axis of rotation C2, as shown in FIG. 17. The horizontal axis of FIG. 17 corresponds to the numerical values indicating each position in the direction of the central axis of rotation C2 shown in FIG. 16. The vertical axis of FIG. 17 indicates the required wear resistance and the mixing ratio of the first ceramic particles 52c. Note that FIG. 16 illustrates the state in which the position of the roller part 49 is indicated using a device 80 that indicates the position of the roller part 49 in the direction of the central axis of rotation C2.

The required wear resistance of the ceramic part 152 is maximum (100%) at position 5 (maximum wear point P1) and position 7 (point P3 symmetrical to maximum wear point P1), as shown by the solid line in Figure 17. For each position away from positions 5 and 7, 10% is subtracted.

The dashed lines indicate the mixing ratio of the 0.5th power of the required wear resistance at each position, the dashed lines indicate the mixing ratio of the squared wear resistance at each position, and the two-dot chain lines indicate the mixing ratio of the 0th power (constant) of the required wear resistance at each position.
17, in the present disclosure, it is preferable that the mixing ratio is the hatched region. Specifically, between positions 1 to 9 where the ceramic part 152 exists, it is preferable that the value of the mixing ratio is smaller than the 0.5 power of the dashed line. From the above, it is preferable that the rate of change of the mixing ratio has a slope of 0.5 or more of the wear resistance required at that position.
If the rate of change in the mixture ratio were to be less than the 0.5th power of the required wear resistance, it would approach the line shown by the two-dot chain line, that is, the mixture ratio of the 0th power (constant = no change) of the required wear resistance at each position. Therefore, the effect of changing the mixture ratio of the ceramic particles depending on the position would be difficult to achieve.

The present disclosure is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and 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.

For example, in each of the above embodiments, a method of changing the material or composition of each ceramic particle is described as a method of making the rigidity, etc. of the first ceramic particle 52c different from that of the second ceramic particle 52d, but the present disclosure is not limited to this. For example, the rigidity and toughness may be made different by changing the particle diameter or particle shape of each ceramic particle. Furthermore, the rigidity and toughness may be made different by combining these.

Furthermore, the thickness of the ceramic portion varies depending on the location of the grinding roller 13. A location where the ceramic portion is thick is likely to achieve a long life even if it has low wear resistance. On the other hand, a location where the ceramic portion is thin is required to have high wear resistance in order to obtain the same life as a location where the ceramic portion is thick. Therefore, the thickness of the ceramic portion may be taken into consideration when determining the mixing ratio of the first ceramic particles 52c in each location.
In addition, in each of the above embodiments, an example in which two types of ceramic particles are mixed has been described, but the present disclosure is not limited to this. For example, three or more types of ceramic particles may be mixed.
It is also desirable that the ceramic particles are thoroughly mixed without bias in each portion.

The crushing roller, the crushing table, the solid fuel crushing device, and the method of manufacturing the crushing roller according to the above-described embodiments can be understood, for example, as follows.
The crushing roller according to the first aspect of the present disclosure is a crushing roller (13) that is housed inside a housing (11), pinches solid fuel between itself and a rotating crushing table (12) to crush the solid fuel, and rotates about a rotation axis (C2) by receiving a rotational force from the crushing table (12). The crushing roller (13) includes a support part (43) that is rotatably supported by the housing (11), and an annular roller part (49) that is fixed to the support part (43) and crushes the solid fuel between itself and the crushing table (12). The roller part (49) is fixed to the support part. The ceramic portion (52, 52A) has a base (51) to which the ceramic portion is fixed, and is provided on the outer periphery of the base (51), the ceramic portion (52, 52A) has a linear expansion coefficient different from that of the base (51) and has better wear resistance than the base (51), and the ceramic portion (52, 52A) has first ceramic particles (52c) and second ceramic particles (52d) having rigidity and toughness different from those of the first ceramic particles (52c), and the mixing ratio of the first ceramic particles (52c) and the second ceramic particles (52d) changes along the direction of the rotation axis (C2).

In the above configuration, the ceramic portion has a mixing ratio of the first ceramic particles and the second ceramic particles having different rigidity and toughness from the first ceramic particles, which varies along the rotation axis direction, thereby making it possible to change the rigidity and toughness of the ceramic portion along the rotation axis direction.
Therefore, for example, when the mixing ratio of ceramics having high rigidity and low toughness is increased in the places that are easily worn, and the mixing ratio of ceramics having low rigidity and high toughness is increased in the other places that are not easily worn, the rigidity of the ceramic part as a whole can be reduced and the toughness can be increased compared to the case where the whole is formed of ceramics having high rigidity and low toughness. Therefore, since the ceramic part is easily able to absorb the thermal stress between the base part and the ceramic part, damage to the ceramic part caused by the difference in linear expansion coefficient can be suppressed. Therefore, the yield when manufacturing the crushing roller can be improved, and the manufacturing cost can be reduced. On the other hand, since the mixing ratio of the first ceramic particles is high in the places that are easily worn, the wear resistance of the crushing roller can be maintained. Therefore, the situation in which the life of the crushing roller is shortened can be suppressed, and the life of the crushing roller can be extended. From the above, the yield when manufacturing the crushing roller can be improved and the life of the crushing roller can be extended.
The mixture ratio of the first ceramic particles and the second ceramic particles includes a case where either one of the ceramics is 100%. That is, the ceramic portion may have a portion where only the first ceramic particles are present, or a portion where only the second ceramic particles are present.

The grinding roller according to the second aspect of the present disclosure is the grinding roller according to the first aspect, wherein the first ceramic particles (52c) have higher rigidity and lower toughness than the second ceramic particles (52d), and the ceramic portion (52, 52A) has a higher mixing ratio of the first ceramic particles (52c) in a first region including a maximum wear point (P1), which is the most susceptible point to wear on the outer circumferential surface of the roller portion (49), than the mixing ratio of the first ceramic particles (52c) in a second region located closer to the end in the direction of the rotation axis (C2) than the first region.

In the above configuration, the mixing ratio of the first ceramic particles in the first region including the maximum wear point is higher than the mixing ratio of the first ceramic particles in the second region located closer to the end of the rotation axis direction than the first region. This makes it possible to improve the rigidity of the first region including the maximum wear point and reduce the toughness. Therefore, it is possible to improve the wear resistance of the grinding roller. This makes it possible to prevent the life of the grinding roller from being shortened and to extend the life of the grinding roller.
On the other hand, since the mixing ratio of the first ceramic particles in the second region is low, the rigidity of the ceramic portion as a whole can be reduced and the toughness can be increased, compared to when the mixing ratio of the first ceramic particles is high in all regions. Therefore, the ceramic portion can easily absorb the thermal stress between the base portion and the ceramic portion, and damage to the ceramic portion caused by the difference in linear expansion coefficient can be suppressed. Therefore, the yield rate when manufacturing the grinding roller can be improved, and the manufacturing cost can be reduced.
In this manner, the above-described configuration can improve the yield in manufacturing the crushing roller and extend the life of the crushing roller.
In addition, in the above configuration, the mixing ratio of the first ceramic particles in the first region including the maximum wear point is higher than the mixing ratio of the first ceramic particles in the second region, so that wear in the region that is easily worn including the maximum wear point is suppressed, and wear in the second region is relatively easy to progress. This makes the amount of wear in the first region including the maximum wear point and the second region uniform. Therefore, it is possible to suppress local wear on the outer surface of the ceramic part. Therefore, it is possible to suppress the deterioration of the meshing between the grinding roller and the grinding table, and therefore to suppress the deterioration of the grinding performance.

The grinding roller according to the third aspect of the present disclosure is the grinding roller according to the second aspect described above, wherein the ceramic portion (52, 52A) has a third region including a point (P3) that is symmetrical to the maximum wear point (P1) with respect to a plane passing through the midpoint of the outer circumferential surface of the roller portion (49) in the direction of the rotation axis (C2), and the mixture ratio of the first ceramic particles (52c) is higher than the mixture ratio of the first ceramic particles (52c) in the second region.

As the wear of the roller portion progresses, the roller portion may be used in an inverted manner. That is, the base end side and the tip end side of the rotation axis direction of the roller portion may be reversed. In this case, the maximum wear point of the roller portion is located symmetrically with respect to a plane passing through the midpoint of the outer circumferential surface.
In the above configuration, the mixing ratio of the first ceramic particles in the third region including the maximum wear point and the target point is higher than the mixing ratio of the first ceramic particles in the second region based on the surface passing through the midpoint of the outer circumferential surface of the roller part. This makes it possible to increase the mixing ratio of the first ceramic particles in the region susceptible to wear even when the roller part is used in an inverted state. Therefore, the life of the grinding roller can be further extended.

The grinding roller according to the fourth aspect of the present disclosure is the grinding roller according to the second aspect, wherein the ceramic portion (52, 52A) has a higher mixing ratio of the first ceramic particles (52c) in the region between the maximum wear point (P1) and a point (P3) symmetrical to the maximum wear point (P1) with respect to a plane passing through the midpoint of the outer circumferential surface of the roller portion (49) in the direction of the rotation axis (C2) than the mixing ratio of the first ceramic particles (52c) in other regions.

In the above configuration, the mixing ratio of the first ceramic particles in the area between the maximum wear point and the target point and the maximum wear point based on the surface passing through the midpoint of the outer circumferential surface of the roller part is higher than the mixing ratio of the first ceramic particles in other areas. This makes it possible to increase the mixing ratio of the first ceramic particles in the area that is prone to wear, even when the roller part is used in an inverted state. Therefore, the life of the grinding roller can be further extended.

The grinding roller according to the fifth aspect of the present disclosure is a grinding roller according to any one of the second to fourth aspects, wherein the ceramic portion (52, 52A) includes a high-mixture portion (52Aa) that includes the first region and has a uniform mixture ratio of the first ceramic particles (52c), and a low-mixture portion (52Ab, 52Ac) that includes the second region, has a uniform mixture ratio of the first ceramic particles (52c), is adjacent to the high-mixture portion (52Aa) in the direction of the rotation axis (C2), and has a lower mixture ratio of the first ceramic particles (52c) than the high-mixture portion (52Aa).

In the above configuration, the ceramic part has a high mixture part in which the mixture ratio of the first ceramic particles is uniform, and a low mixture part that is adjacent to the high mixture part in the rotation axis direction and has a uniform mixture ratio of the first ceramic particles and a lower mixture ratio of the first ceramic particles than the high mixture part. A part in which the mixture ratio of the first ceramic particles is uniform is easier to manufacture than a part in which the mixture ratio is not uniform. As a result, by simply manufacturing a high mixture part and a low mixture part that have different but uniform mixture ratios and arranging the high mixture part and the low mixture part side by side in the rotation axis direction, it is possible to easily manufacture a ceramic part in which the mixture ratio of the first ceramic particles changes in the rotation axis direction of the ceramic part.

The grinding table according to the first aspect of the present disclosure is a grinding table (12) that is housed inside a housing (11), rotates around a central axis (C1) by a driving force transmitted from a driving unit (15), and grinds solid fuel by sandwiching the solid fuel between the grinding roller (13). The grinding table (12) includes a table portion (12a) to which the solid fuel is supplied, the table portion (12a) includes a base portion (12c) and a ceramic portion (12d) that is provided on the upper surface of the base portion (12c) and has a linear expansion coefficient different from that of the base portion (12c) and is more wear-resistant than the base portion (12c). The ceramic portion (12d) includes first ceramic particles (52c) and second ceramic particles (52d) that have different rigidity and toughness from the first ceramic particles (52c), and the mixture ratio of the first ceramic particles (52c) and the second ceramic particles (52d) changes along the radial direction based on the central axis (C1).

In the above configuration, the mixture ratio of the first ceramic particles and the second ceramic particles having different rigidity and toughness from the first ceramic particles changes along the radial direction of the grinding table, so that the rigidity and toughness of the ceramic portion can be changed along the radial direction of the grinding table.
Therefore, for example, when the mixing ratio of ceramics having high rigidity and low toughness is increased in the places that are easily worn, and the mixing ratio of ceramics having low rigidity and high toughness is increased in the other places that are not easily worn, the rigidity of the ceramic part as a whole can be reduced and the toughness can be increased compared to the case where the whole is formed of ceramics having high rigidity and low toughness. Therefore, since the ceramic part is easily able to absorb the thermal stress between the base part and the ceramic part, damage to the ceramic part caused by the difference in linear expansion coefficient can be suppressed. Therefore, the yield when manufacturing the grinding table can be improved, and the manufacturing cost can be reduced. On the other hand, since the mixing ratio of the first ceramic particles is high in the places that are easily worn, the wear resistance of the grinding table can be maintained. Therefore, the situation in which the life of the grinding table is shortened can be suppressed, and the life of the grinding table can be extended. From the above, the yield when manufacturing the grinding table can be improved and the life of the grinding table can be extended.
The mixture ratio of the first ceramic particles and the second ceramic particles includes a case where either one of the ceramics is 100%. That is, the ceramic portion may have a portion where only the first ceramic particles are present, or a portion where only the second ceramic particles are present.

The grinding table according to the second aspect of the present disclosure is the grinding table according to the first aspect, wherein the first ceramic particles (52c) have higher rigidity and lower toughness than the second ceramic particles (52d), and the ceramic portion (12d) has a higher mixing ratio of the first ceramic particles (52c) in a first region including a maximum wear point (P2), which is the most susceptible point to wear on the upper surface of the table portion (12a), in the radial direction, than the mixing ratio of the first ceramic particles (52c) in a second region located closer to the end in the direction of the rotation axis (C2) than the first region.

In the above configuration, the mixing ratio of the first ceramic particles in the region including the maximum wear point is higher than the mixing ratio of the first ceramic particles in the second region located closer to the end of the rotation axis direction than the first region. This makes it possible to improve the rigidity of the first region including the maximum wear point and reduce the toughness. Therefore, it is possible to improve the wear resistance of the grinding table. This makes it possible to prevent the life of the grinding table from being shortened and to extend the life of the grinding table.
On the other hand, since the mixing ratio of the first ceramic particles in the second region is low, the rigidity of the ceramic part as a whole can be reduced and the toughness can be increased compared to the case where the mixing ratio of the first ceramic particles is high in all regions. Therefore, the ceramic part can easily absorb the thermal stress between the base part and the ceramic part, so that damage to the ceramic part caused by the difference in linear expansion coefficient can be suppressed. Therefore, the yield rate when manufacturing the grinding table can be improved, and the manufacturing cost can be reduced.
In this way, with the above configuration, the yield rate when manufacturing the rotary table can be improved, and the rotary table can have a longer life.

The solid fuel pulverizing device according to the first aspect of the present disclosure includes a pulverizing roller as described in any one of the first to fifth aspects and/or a pulverizing table as described in the first or second aspect.

The manufacturing method of the grinding roller according to the first aspect of the present disclosure is a manufacturing method of a grinding roller (13) that is housed inside a housing (11), grinds solid fuel by sandwiching the solid fuel between the grinding roller (13) and a rotating grinding table (12), and rotates around a rotation axis (C2) by receiving a rotational force from the grinding table (12). The grinding roller (13) comprises a support part (43) that is rotatably supported with respect to the housing (11), and an annular roller part (49) that is fixed to the support part (43) and grinds the solid fuel between the grinding table (12), and the roller part (49) comprises a base part (51) that is fixed to the support part and , and a ceramic part (52, 52A) provided on the outer periphery of the base (51) and having a linear expansion coefficient different from that of the base (51) and superior wear resistance to the base (51), the ceramic part (52, 52A) has first ceramic particles (52c) and second ceramic particles (52d) having rigidity and toughness different from those of the first ceramic particles (52c), the mixing ratio of the first ceramic particles (52c) and the second ceramic particles (52d) changes along the direction of the rotation axis (C2), and the base (51) and the ceramic part (52, 52A) are integrally molded by casting.

The method for manufacturing a grinding roller according to the second aspect of the present disclosure is the method for manufacturing a grinding roller according to the first aspect, in which the ceramic portion (52, 52A) has a high mixture portion (52Aa) having a high mixture ratio of the first ceramic particles (52c) and a low mixture portion (52Ab, 52Ac) that is adjacent to the high mixture portion (52Aa) in the direction of the rotation axis (C2) and has a lower mixture ratio of the first ceramic particles (52c) than the high mixture portion (52Aa), and includes a ceramic portion (52, 52A) arrangement step of arranging the ceramic portion (52, 52A) at a predetermined position in the mold (60) with the high mixture portion (52Aa) and the low mixture portion (52Ab, 52Ac) fixed.

The above configuration includes a ceramic part placement process in which the ceramic part is placed at a predetermined location in the mold while the high-mixture part and low-mixture part are fixed. This allows the ceramic part to be placed with the relative positions of the high-mixture part and low-mixture part determined, making it easy to place the ceramic part. Therefore, a grinding roller having a high-mixture part and a low-mixture part can be easily manufactured.

The manufacturing method of the grinding roller according to the third aspect of the present disclosure is the manufacturing method of the grinding roller according to the first aspect, in which the ceramic portion (52, 52A) has a high mixture portion (52Aa) having a high mixture ratio of the first ceramic particles and a low mixture portion (52Ab, 52Ac) that is adjacent to the high mixture portion (52Aa) in the direction of the rotation axis (C2) and has a lower mixture ratio of the first ceramic particles than the high mixture portion (52Aa), and includes a high mixture portion fixing step of fixing the high mixture portion (52Aa) to a predetermined position of the mold (60) by a high mixture portion fixing portion (FAa), and a low mixture portion fixing step of fixing the low mixture portion (52Ab, 52Ac) to a predetermined position of the mold (60) by a low mixture portion fixing portion (FAb, FAc).

The above configuration includes a high-mixture section fixing process in which the high-mixture section is fixed to a predetermined location in the mold by the high-mixture section fixing section, and a low-mixture section fixing process in which the low-mixture section is fixed to a predetermined location in the mold by the low-mixture section fixing section. This makes it possible to easily fix the high-mixture section and the low-mixture section to the predetermined locations in the mold. Therefore, a grinding roller having a high-mixture section and a low-mixture section can be easily manufactured.

1: Power plant 10: Mill 11: Housing 12: Grinding table 12a: Table section 12b: Support section 12c: Base section 12d: Ceramic section 12da: High mixing section 12db: Medium mixing section 12dc: Low mixing section 13: Grinding roller 14: Reducer 15: Mill motor 16: Rotary classifier 16a: Blade 17: Coal feed pipe 18: Classifier motor 19: Outlet port 21: Bunker 22: Downspout section 25: Coal feeder 26: Conveyor section 27: Coal feeder motor 30: Blower section 30a: Hot gas flow path 30b: Cold gas flow path 30c: Hot gas damper 30d: Cold gas damper 31: Primary air fan 34: Air preheater 40: Status detection section 41: Bottom section 42: Ceiling section 43 : journal housing 44 : journal shaft 45 : journal head 46 : pressing device 47 : support arm 48 : support shaft 49 : roller portion 49a : outer peripheral surface 50 : control portion 51 : base portion 51a : outer peripheral surface 52 : ceramic portion 52A : ceramic portion 52Aa : high mixing portion 52Ab : medium mixing portion 52Ac : low mixing portion 52a : outer peripheral surface 52b : base material 52c : first ceramic particles 52d : second ceramic particles 53 : fixing member 60 : mold 61 : sprue 62 : runner 80 : device 100 : solid fuel pulverizing device 110 : primary air passage 120 : pulverized fuel supply pipe 152 : ceramic portion 200 : boiler 210 : furnace 220 : burner CB : ceramic block CBA : ceramic block CBAa : high mixing block CBAb : Middle mixing block CBAc : Low mixing block CBa : Upper surface CP : Center point FAa : High mixing section fixing section FAb : Middle mixing section fixing section FAc : Low mixing section fixing section

Claims (11)

a crushing roller that is accommodated in a housing, that crushes solid fuel by pinching the solid fuel between itself and a rotating crushing table, and that rotates about a rotation axis when subjected to a rotational force from the crushing table,
a support portion rotatably supported relative to the housing;
a circular roller portion fixed to the support portion and configured to crush the solid fuel between the roller portion and the crushing table,
the roller portion has a base portion fixed to the support portion, and a ceramic portion provided on an outer periphery of the base portion, the ceramic portion having a linear expansion coefficient different from that of the base portion and having a higher wear resistance than the base portion,
The ceramic portion has first ceramic particles and second ceramic particles having rigidity and toughness different from the first ceramic particles, and the mixing ratio of the first ceramic particles to the second ceramic particles changes along the rotation axis direction of the grinding roller. The first ceramic particles have higher rigidity and lower toughness than the second ceramic particles;
2. The grinding roller according to claim 1, wherein the ceramic portion has a mixing ratio of the first ceramic particles in a first region including a maximum wear point, which is the point on the outer peripheral surface of the roller portion that is most susceptible to wear, higher than a mixing ratio of the first ceramic particles in a second region located toward the end of the rotation axis direction relative to the first region. The grinding roller according to claim 2, wherein the ceramic portion has a higher mixing ratio of the first ceramic particles in a third region including a point symmetrical to the maximum wear point with respect to a plane passing through the midpoint of the outer circumferential surface of the roller portion in the direction of the rotation axis than in the second region. The grinding roller according to claim 2, wherein the ceramic part has a higher mixing ratio of the first ceramic particles in the region between the maximum wear point and a point symmetrical to the maximum wear point with respect to a plane passing through the midpoint of the outer circumferential surface of the roller part in the direction of the rotation axis than in other regions. The grinding roller according to any one of claims 2 to 4, wherein the ceramic portion has a high mixing portion that includes the first region and has a uniform mixing ratio of the first ceramic particles, and a low mixing portion that includes the second region, has a uniform mixing ratio of the first ceramic particles, is adjacent to the high mixing portion in the direction of the rotation axis, and has a lower mixing ratio of the first ceramic particles than the high mixing portion. a crushing table that is accommodated in a housing and rotates about a central axis by a driving force transmitted from a driving unit, and crushes solid fuel by sandwiching the solid fuel between the crushing rollers,
a table portion to which the solid fuel is supplied,
the table portion has a base portion and a ceramic portion provided on an upper surface of the base portion, the ceramic portion having a linear expansion coefficient different from that of the base portion and having higher wear resistance than the base portion,
The ceramic portion has first ceramic particles and second ceramic particles having rigidity and toughness different from those of the first ceramic particles, and the mixing ratio of the first ceramic particles to the second ceramic particles changes along the radial direction based on the central axis. The first ceramic particles have higher rigidity and lower toughness than the second ceramic particles;
The grinding table according to claim 6, wherein in the ceramic portion, a mixing ratio of the first ceramic particles in a first region including a maximum wear point, which is a point on the upper surface of the table portion that is most susceptible to wear in the radial direction, is higher than a mixing ratio of the first ceramic particles in a second region located closer to the end in the rotation axis direction than the first region. A solid fuel pulverizer equipped with the pulverizing roller according to claim 1 and/or the pulverizing table according to claim 6. A method for manufacturing a crushing roller that is housed inside a housing, that crushes solid fuel by sandwiching the solid fuel between itself and a rotating crushing table, and that rotates about a rotation axis thereof by receiving a rotational force from the crushing table, comprising the steps of:
The crushing roller is
a support portion rotatably supported relative to the housing;
a circular roller portion fixed to the support portion and configured to crush the solid fuel between the roller portion and the crushing table,
the roller portion has a base portion fixed to the support portion, and a ceramic portion provided on an outer periphery of the base portion, the ceramic portion having a linear expansion coefficient different from that of the base portion and having a higher wear resistance than the base portion,
the ceramic portion has first ceramic particles and second ceramic particles having rigidity and toughness different from those of the first ceramic particles, and a mixing ratio of the first ceramic particles to the second ceramic particles changes along the rotation axis direction,
A method for manufacturing a crushing roller comprising the step of integrally molding the base portion and the ceramic portion by casting. the ceramic portion has a high mixture portion having a high mixture ratio of the first ceramic particles, and a low mixture portion provided adjacent to the high mixture portion in the rotation axis direction and having a lower mixture ratio of the first ceramic particles than the high mixture portion,
10. The method for producing a crushing roller according to claim 9, further comprising a ceramic part disposing step of disposing the ceramic part at a predetermined position in a mold while the high mixture part and the low mixture part are fixed. the ceramic portion has a high mixture portion having a high mixture ratio of the first ceramic particles, and a low mixture portion provided adjacent to the high mixture portion in the rotation axis direction and having a lower mixture ratio of the first ceramic particles than the high mixture portion,
a high-mixture portion fixing step of fixing the high-mixture portion to a predetermined location of a mold by a high-mixture portion fixing part;
The method for manufacturing a crushing roller according to claim 9, further comprising a low-mixture portion fixing step of fixing the low-mixture portion to a predetermined position of the mold by a low-mixture portion fixing portion.