JP7703337B2 - Rotary valve, supply device, power generation plant, and method of operating the rotary valve - Google Patents

Description

The present disclosure relates to a rotary valve , a supply apparatus and a power plant, and a method of operating the rotary valve.

Conventionally, solid fuels (carbon-containing solid fuels) such as coal and biomass fuels 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, solid fuels such as coal and biomass fuels fed onto a pulverizing table are pinched between the pulverizing table and a pulverizing roller to pulverize them, and from the pulverized solid fuel that has been pulverized into fine powder by a conveying gas (primary air) supplied from the periphery of the pulverizing table, fine fuels within a specified particle size range are selected by a classifier, transported to a boiler, and burned in a 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.

Among carbon-containing solid fuels, biomass fuels such as wood-based fuels have the property of being difficult to pulverize, but have the property of being highly combustible and being able to be burned suitably even if the particle size is relatively large. Therefore, when using biomass fuel as a solid fuel, it is usually supplied from a mill to a combustion device installed in a boiler in a state of particle size about 5 to 10 times larger than that of coal.
Thus, since coal and biomass fuel have different particle sizes to be supplied to the combustion device, it is preferable that the mill for pulverizing and classifying the solid fuel is designed separately for biomass fuel pulverization and coal pulverization (e.g., housing shape, rotation speed of the pulverization table, and rotation speed of the classifier, etc.). However, from the viewpoint of equipment cost, installation space, etc., it is desirable to be able to use the same mill for both solid fuels, biomass fuel and coal, and to be able to use biomass fuel using the mill that can be used for both coal and biomass fuel.

In order to use coal and biomass fuel in the same mill, there is an increasing need to pulverize biomass fuel in a coal mill. When pulverizing biomass fuel in a coal mill, biomass pellets may be used. Biomass pellets have a lower specific gravity than coal, and have a relatively uniform particle size, so there are no fine particles to fill the gaps between the particles. For this reason, the pressure loss in the particle-packed bed is small, and sufficient material sealing effect cannot be obtained, and there is a possibility that the conveying gas will blow by (backflow) from the mill to the bunker. The conveying gas is at a high temperature due to drying the solid fuel, and if it blows into the bunker, it may cause the solid fuel stored in the bunker to become hot. For this reason, when pulverizing biomass pellets, a rotary valve may be provided between the coal feeder and the mill to ensure sealing, thereby suppressing the conveying gas from blowing by from the mill to the bunker. For example, the system described in Patent Document 1 is known as a system provided with such a rotary valve.

JP 2019-39617 A

Currently, in order to meet the social demand for a low-carbon society, the demand for biomass fuel is growing significantly and the supply is unstable. For this reason, there is a growing need to be able to easily switch between coal and biomass fuel depending on the fuel availability.
The rotary valve is essential when biomass pellets are used as fuel. On the other hand, the rotary valve is not necessary when coal is used as fuel. Generally, the wear of coal is higher than that of biomass fuel, so if a rotary valve is used when coal is used, the valve body of the rotary valve may wear, resulting in a decrease in sealing performance and a shortened lifespan. For this reason, as in the method described in Patent Document 1, it is possible to replace the piping for supplying solid fuel with a straight pipe without a rotary valve and a pipe with a rotary valve, depending on the solid fuel used. However, in general, rotary valves are manufactured to be thick in order to ensure wear resistance, and therefore are heavy. In addition, they are installed in a narrow space between a coal feeder and a mill. For this reason, the method described in Patent Document 1 may result in heavy labor for replacing the piping.

The present disclosure has been made in consideration of the above circumstances, and aims to provide a rotary valve, a supply device, a power generation plant , and an operating method for a rotary valve that can easily switch between a state in which the rotary valve suppresses blow-through and a state in which the rotary valve does not come into contact with solid fuel.

In order to solve the above problems, the rotary valve, the power plant, and the method of operating the rotary valve of the present disclosure employ the following measures.
A rotary valve according to one embodiment of the present disclosure is provided in a solid fuel supply pipe that supplies solid fuel to a pulverizer that pulverizes the solid fuel, and is a rotary valve that suppresses gas blow-by from the pulverizer, and includes a casing that forms an outer shell, a rotating shaft that is rotatably supported about a central axis extending in a direction intersecting the flow direction of the solid fuel, and a valve body that is fixed to the rotating shaft and housed inside the casing and suppresses gas blow-by in the solid fuel supply pipe, the casing having a passing space defining portion that defines a passing space through which the solid fuel flowing inside the solid fuel supply pipe passes, and an evacuation space defining portion that defines an evacuation space through which the solid fuel flowing inside the solid fuel supply pipe does not pass, the passing space and the evacuation space are aligned in a direction along the central axis, and the valve body is movable between the passing space and the evacuation space.

A method of operating a rotary valve according to one aspect of the present disclosure is a method of operating a rotary valve that is provided in a solid fuel supply pipe that supplies solid fuel to a pulverizer that pulverizes the solid fuel, and that suppresses gas blow-through from the pulverizer, the rotary valve comprising a housing forming an outer shell, a rotating shaft that is supported rotatably about a central axis that extends in a direction intersecting the flow direction of the solid fuel, and a valve body that is fixed to the rotating shaft and housed inside the housing and suppresses gas blow-through within the solid fuel supply pipe, the housing having an inner The valve body has a passage space defining portion that defines a passage space through which the solid fuel circulating in the solid fuel supply pipe passes, and an evacuation space defining portion that defines an evacuation space through which the solid fuel circulating in the solid fuel supply pipe does not pass, the passage space and the evacuation space are aligned in a direction along the central axis, the valve body is movable between the passage space and the evacuation space, and includes an evacuation process for moving the valve body from the passage space to the evacuation space, and an installation process for moving the valve body from the evacuation space to the passage space.

According to the present disclosure, it is possible to easily switch between a state in which the rotary valve suppresses blow-by and a state in which the rotary valve does not come into contact with the solid fuel.

FIG. 2 is a configuration diagram showing a solid fuel pulverizer and a boiler according to an embodiment of the present disclosure. FIG. 1 is a schematic diagram illustrating a configuration of a solid fuel pulverizer and a boiler according to an embodiment of the present disclosure. FIG. 1 is a schematic front view showing a rotary valve according to a first embodiment of the present disclosure. 4 is a graph showing a method of operating the rotary valve according to the first embodiment of the present disclosure, illustrating the relationship between solid fuel supplied to the mill and the position of the valve disc. FIG. 4 is a schematic front view showing a rotary valve according to a second embodiment of the present disclosure. FIG. 11 is a schematic front view showing a rotary valve according to a third embodiment of the present disclosure. FIG. 11 is a schematic front view showing a rotary valve according to a fourth embodiment of the present disclosure. FIG. 13 is a schematic front view showing a rotary valve according to a fifth embodiment of the present disclosure. FIG. 13 is a schematic front view showing a rotary valve according to a sixth embodiment of the present disclosure. FIG. 13 is a perspective view showing a rotating shaft of a rotary valve according to a sixth embodiment of the present disclosure. FIG. 13 is a schematic front view showing a rotary valve according to a seventh embodiment of the present disclosure. FIG. 13 is a schematic front view showing a rotary valve according to an eighth embodiment of the present disclosure. FIG. 13 is a schematic front view showing a rotary valve according to a ninth embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a rotary valve , a supply device , a power plant, and an operating method of a rotary valve 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 pulverization device 100 of this embodiment is a device that pulverizes solid fuel (carbon-containing solid fuel) such as coal or biomass fuel, generates pulverized fuel, and supplies it to a burner (combustion device) 220 of a boiler 200.
The power plant 1 including the solid fuel pulverizer 100 and the boiler 200 shown in FIG. 1 is equipped with one solid fuel pulverizer 100, but it may also be a system equipped with multiple solid fuel pulverizers 100 corresponding to each of the multiple burners 220 of one boiler 200.

The solid fuel pulverizer 100 of this embodiment includes a mill (pulverizer) 10, a coal feeder (fuel supplier) 20, a blower (carrier gas supplier) 30, a state detector 40, and a controller (determiner) 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 of biomass fuels are being considered.

The mill 10 comprises a housing 11, a grinding table (rotary table) 12, grinding rollers 13, a drive unit 14, a mill motor 15 connected to the drive unit 14 and driving the grinding table 12 to rotate, a rotary classifier 16, a fuel supply unit 17, 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 fuel supply unit 17.
A fuel supply unit 17 is attached to the center of the ceiling portion 42 of the housing 11. This fuel supply unit 17 supplies solid fuel guided from the bunker 21 into the housing 11, and is disposed in the vertical direction at the center position of the housing 11 with its lower end extending into the interior of the housing 11.

A drive unit 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 drive unit 14.
The grinding table 12 is a circular member in a plan view, and is disposed so as to face the lower end of the fuel supply unit 17. The upper surface of the grinding table 12 may have an inclined shape, for example, low at the center and high toward the outside, and the outer periphery may have a shape that is curved upward. The fuel supply unit 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 grinds the supplied solid fuel between the grinding roller 13.

When solid fuel is fed from the fuel supply unit 17 toward the approximate center region of the grinding table 12, the centrifugal force generated by the rotation of the grinding table 12 guides the solid fuel 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) 100a, 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 100a 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 fuel supply unit 17. The crushing roller 13 is pressed against the upper surface of the crushing table 12 and cooperates with the crushing table 12 to crush the solid fuel.
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 swing up and down by the journal head 45, and is supported so as to be able to move toward and away from the upper surface of the crushing table 12. When the crushing table 12 rotates, the crushing roller 13 receives a rotational force from the crushing table 12 and rotates with it, with the outer circumferential surface of the crushing roller 13 in contact with the solid fuel on the upper surface of the crushing table 12. When solid fuel is supplied from the fuel supply unit 17, the solid fuel is pressed between the crushing roller 13 and the crushing table 12 and crushed.

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, allowing the crushing roller 13 to swing up and down around the support shaft 48. A pressing device 49 is provided on the upper end part vertically above the support arm 47. The pressing device 49 is fixed to the housing 11, and applies a load to the crushing roller 13 via the support arm 47 etc. so as to press the crushing roller 13 against the crushing table 12.

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

The rotary classifier 16 is provided at the top of the housing 11 and has a hollow, generally inverted cone-shaped exterior. 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 fuel having a particle size larger than a predetermined particle size (for example, 70 to 100 μm for coal) (hereinafter, the pulverized fuel having a particle size larger than the predetermined particle size is referred to as "coarse pulverized fuel") and fuel having a particle size smaller than the predetermined particle size (hereinafter, the pulverized fuel having a particle size smaller than the predetermined particle size is referred to as "fine pulverized fuel"). The rotary classifier 16 that classifies by rotation is also called a rotary separator, and is given a rotational driving force by a classifier motor 18 controlled by a control unit 50, and rotates around a fuel supply unit 17 centered on a cylindrical axis (not shown) extending in the vertical direction of the housing 11.
The classifier may be a fixed classifier having a fixed hollow inverted cone-shaped casing and a plurality of fixed 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 where it is pulverized again, 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 from the outlet port 19 together with the primary air into the fine fuel supply passage 100b and supplied to the burner 220 of the boiler 200. When the solid fuel is coal, the fine fuel supply passage 100b is also called a pulverized coal pipe.

The fuel supply unit 17 is attached so that its lower end extends vertically into the interior of the housing 11, penetrating the ceiling portion 42 of the housing 11, and supplies solid fuel fed from the top of the fuel supply unit 17 to the approximate center region of the grinding table 12. The fuel supply unit 17 receives solid fuel from the coal feeder 20.

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

On the other hand, biomass fuel chips or pellets before crushing have a constant particle size (pellet size is, for example, about 6 to 8 mm in diameter and about 40 mm or less in length) and are lightweight compared to coal fuel (i.e., coal before crushing has a particle size of, for example, about 2 to 50 mm). Therefore, when biomass fuel is stored in downspout 24, the gaps formed between each biomass fuel in the solid fuel layer in downspout 24 are larger than in the case of coal fuel. Also, the state of the gaps formed between each biomass fuel in the solid fuel layer in downspout 24 is not necessarily constant and may fluctuate.
Therefore, compared to the case of coal fuel, relatively large gaps are formed between the biomass fuel chips and pellets in the downspout 24, and as a result, primary air and pulverized fuel from inside the mill 10 pass through the gaps formed in the solid fuel layer, causing a backflow of primary air and pulverized fuel from inside the mill 10 through the coal feeder 20 to the bunker 21, which can cause a drop in the pressure inside the mill 10, and this is more likely to occur than in the case of coal fuel.
In addition, if the primary air and pulverized fuel flow back toward the bunker 21 and the pressure inside the mill 10 drops, various problems may occur in the stable operation of the solid fuel pulverizing apparatus 100 and the boiler 200, such as a deterioration in the transportability of the pulverized fuel inside the mill 10, dust generation inside the coal feeder 20 and at the top of the bunker 21, ignition of the solid fuel inside the coal feeder 20, the bunker 21, and the downspout 24, and a reduction in the amount of pulverized fuel transported to the burner 220.
For this reason, in this embodiment, a rotary valve 60 (see FIG. 2) is provided in the fuel supply section (solid fuel supply pipe) 17 leading from the coal feeder 20 to the inside of the mill 10 to suppress the occurrence of backflow (blow-by) of primary air and pulverized fuel leading from the inside of the mill 10 through the fuel supply section 17 and the coal feeder 20 to the bunker 21. Note that the rotary valve 60 is omitted in FIG. 1 for illustration purposes. Details of the rotary valve 60 will be described later.

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 inside of the housing 11, in this embodiment, the blower section 30 is equipped with a primary air fan (PAF) 31, a hot gas flow path 30a, a cold gas flow path 30b, a hot gas damper 30c, and a cold gas damper 30d.

In this embodiment, the hot gas flow path 30a supplies a portion of the air (outside air) sent out from the primary air ventilator 31 as hot gas that has been heated by passing through a heat exchanger 34, such as an air preheater. A hot gas damper 30c is provided downstream of the hot gas flow path 30a. The opening degree of the hot gas damper 30c is controlled by the control unit 50. The flow rate of the hot gas supplied from the hot gas flow path 30a is determined by the opening degree of the hot gas damper 30c.

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 downstream of the cold gas flow path 30b. The opening degree of the cold gas damper 30d is controlled by the control unit 50. The flow rate of the cold gas supplied from the cold gas flow path 30b is determined by the opening degree of the cold gas damper 30d.

In 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.
In addition, the oxygen concentration of the primary air blown from the primary air passage 100a to the inside of the housing 11 may be adjusted by introducing a portion of the combustion gas discharged from the boiler 200 via a gas recirculation fan (not shown) into the hot gas supplied from the hot gas passage 30a and mixing it.

In this embodiment, the state detection unit 40 of the mill 10 transmits measured or detected data 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 between the pressure at the portion where the primary air flows into the inside of the housing 11 from the primary air flow passage 100a 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 flow passage 100b as the differential pressure of the mill 10. 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 of the mill 10, the amount of pulverized fuel discharged from the outlet port 19 can be adjusted in relation to the amount of solid fuel supplied to the mill 10.Therefore, within the range in which the particle size of the pulverized fuel does not affect the combustibility of the burner 220, an amount of pulverized fuel corresponding to the amount of solid fuel supplied to the mill 10 can be stably supplied to the burner 220 provided in the boiler 200.
The state detection unit 40 in 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 (the temperature of the primary air at the mill inlet) and the temperature of the primary air from the space above the grinding table 12 inside the housing 11 to the outlet port 19, and controls the blower unit 30 so that the temperature does not exceed the upper limit temperature. The upper limit temperature is determined taking into consideration the possibility of ignition of the solid fuel, etc. The primary air is cooled inside the housing 11 by transporting the pulverized fuel while drying it, and the temperature of the primary air at the outlet port 19 is, for example, about 60 to 90 degrees.

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 optimizes the differential pressure of the mill 10, i.e., the circulation amount of pulverized fuel inside the mill 10, within a predetermined range, thereby enabling a stable supply of pulverized fuel to the burner 220.
In addition, the control unit 50 can adjust the amount of solid fuel supplied (coal supply amount) that the conveying unit 22 conveys and supplies to the fuel supply unit 17 by, for example, transmitting a drive instruction to the coal supply motor 23 of the coal supply unit 20.
Furthermore, the control unit 50 can adjust the flow rate and temperature of the primary air by controlling the opening of the hot gas damper 30c and the cold gas damper 30d by transmitting an opening instruction 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 become predetermined values set in accordance with the amount of coal feed for each type of solid fuel.

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, which generates steam by burning the 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 primary air containing pulverized fuel supplied from the pulverized fuel supply passage 100b and secondary air supplied by heating air (outside air) sent out from a forced draft fan (FDF: Forced Draft Fan) 32 in a heat exchanger 34. The pulverized fuel is burned in the furnace 210, and the high-temperature combustion gas is exhausted 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 a predetermined treatment in an environmental device (such as a denitration device or an electric dust collector, not shown), and then undergoes heat exchange between the air discharged from the primary air fan 31 and the air discharged from the forced draft fan 32 in a heat exchanger 34, such as an air preheater, and is then guided to a chimney (not shown) via an induced draft fan (IDF) 33 and released into the outside air. The air discharged from the primary air fan 31, heated by the combustion gas in the heat exchanger 34, is supplied to the above-mentioned hot gas flow path 30a.
The water supplied to each heat exchanger of 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 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 rotary valve 60 will be described in detail with reference to FIGS.
2 and 3, the rotary valve 60 is provided in the middle of the fuel supply section 17. As shown in Fig. 3, the rotary valve 60 includes a casing (housing) 61 forming an outer shell, a rotary shaft 62 supported by the casing 61 so as to be rotatable about a central axis C extending in the horizontal direction, and a valve body 63 housed inside the casing 61.
In the rotary valve 60 according to this embodiment, a valve body 63 rotating inside a casing 61 can slide in a direction along a central axis C of a rotating shaft 62 (hereinafter referred to as the "axial direction"), and a retraction space for the valve body is provided inside the casing 61. When a sealing function (a function for suppressing blow-through) is required as a rotary valve, such as when the mill 10 grinds biomass fuel as a solid fuel, the valve body 63 slides into the passage space for the solid fuel to exert the sealing function. On the other hand, when the sealing function of the rotary valve is no longer required, such as when the mill 10 grinds coal, the valve body 63 slides into the retraction space, allowing the valve body to be retracted from the flow path of the solid fuel.

The casing 61 has a passage space S1 through which the solid fuel passes and an evacuation space S2 into which the valve body 63 retreats formed therein. The casing 61 integrally includes a passage space defining portion 61a that defines the passage space S1, an evacuation space defining portion 61b that defines the evacuation space S2, an upstream flow path portion 61c that is connected to the upper end of the passage space defining portion 61a, and a downstream flow path portion 61d that is connected to the lower end of the passage space defining portion 61a.

The passage space S1 is located vertically below the upstream fuel supply section 17a and vertically above the downstream fuel supply section 17b. In other words, the passage space S1 is located so as to overlap with the fuel supply section 17 when the fuel supply section 17 is viewed from the central axis direction. The passage space S1 forms part of the flow path of the solid fuel from the coal feeder 20 to the mill 10.

The evacuation space S2 is a space through which solid fuel does not pass. The evacuation space S2 is positioned so as not to overlap with the fuel supply unit 17 when viewed from the central axis direction of the fuel supply unit 17. The evacuation space S2 and the passage space S1 are aligned in a direction intersecting the flow direction of the solid fuel. There is no partition or the like between the evacuation space S2 and the passage space S1, and the evacuation space S2 and the passage space S1 are connected.

The passage space defining portion 61a is a box-shaped member with openings formed at the upper and lower ends. The upstream flow passage portion 61c is connected to the opening formed at the upper end. The downstream flow passage portion 61d is connected to the opening formed at the lower end. The rotation shaft 62 penetrates the side wall of the passage space defining portion 61a (the side wall facing away from the evacuation space S2). One end of the passage space defining portion 61a in a direction intersecting the flow direction of the solid fuel (the end on the evacuation space S2 side) is connected to the evacuation space defining portion 61b. The passage space defining portion 61a protrudes on both sides of the upstream flow passage portion 61c and the downstream flow passage portion 61d in a direction intersecting the flow direction of the solid fuel.

The evacuation space defining portion 61b is a box-shaped member. The rotating shaft 62 penetrates the side wall of the evacuation space defining portion 61b (the side wall facing away from the passage space S1). In addition, the sealing gas supply pipe 70 that supplies sealing gas to the evacuation space S2 penetrates the side wall.

The upstream flow passage section 61c is a cylindrical member extending in the vertical direction. The diameter of the upstream flow passage section 61c is the same as the diameter of the upstream fuel supply section 17a. At the upper end of the upstream flow passage section 61c, an upstream flange 61e extending radially outward is provided over the entire circumferential area. The upper surface of the upstream flange 61e is in surface contact with the lower surface of the supply section flange 17c provided at the lower end of the upstream fuel supply section 17a. The rotary valve 60 and the upstream fuel supply section 17a are fixed by a plurality of upper bolts 61g that pass through the upstream flange 61e and the supply section flange 17c.

The downstream flow passage 61d is a cylindrical member extending in the vertical direction. The diameter of the downstream flow passage 61d is the same as the diameter of the downstream fuel supply portion 17b. A downstream flange 61f extending radially outward is provided at the lower end of the downstream flow passage 61d over the entire circumferential area. The lower surface of the downstream flange 61f is in surface contact with the upper surface of the supply portion flange 17d provided at the upper end of the downstream fuel supply portion 17b. The rotary valve 60 and the downstream fuel supply portion 17b are fixed by a plurality of lower bolts 61h that pass through the downstream flange 61f and the supply portion flange 17d.
As will be described later, in this embodiment, the valve body 63 slides in a direction intersecting the flow direction of the solid fuel. The sliding movement of the valve body 63 causes a large fluctuation in the center of gravity of the rotary valve 60. In particular, when the weight of the valve body 63 is heavy, the rotary valve 60 may tip over as the valve body 63 slides. Therefore, each flange and bolt is designed to have a strength sufficient to withstand the tipping moment generated by the sliding movement of the valve body 63.

The rotating shaft 62 is a cylindrical member extending horizontally. A valve body 63 is fixed to approximately the center of the rotating shaft 62 in the axial direction. The axial length of the rotating shaft 62 is longer than the axial length of the casing 61. Therefore, the rotating shaft 62 penetrates the side wall of the casing 61.

The rotating shaft 62 rotates about the central axis C by the driving force from the motor 71. That is, the rotating shaft 62 is rotatably supported by the casing 61. The rotating shaft 62 slides in the axial direction by the cylinder 73. That is, the rotating shaft 62 is slidably supported by the casing 61. The cylinder 73 is disposed above the evacuation space defining portion 61b. By disposing the cylinder 73 in this manner, the space above the evacuation space defining portion 61b can be effectively utilized, so that the rotary valve 60 can be made compact. One end of the rotating shaft 62 in the axial direction and the cylinder 73 are connected by an L-shaped rod 74. The rod 74 and the rotating shaft 62 are fixed so that the rotation of the rotating shaft 62 is permitted.
The cylinder 73 may be driven by hydraulic pressure supplied from a hydraulic pressure generating device (not shown) provided outside the rotary valve 60. The device for sliding the rotary shaft 62 may be a device other than the cylinder 73 as long as it does not impede the rotation of the rotary shaft 62 and the valve body 63, and may be, for example, a ball screw.

The driving force of the motor 71 is transmitted to the rotating shaft 62 via a sprocket 72, etc. In this embodiment, the motor 71 and the sprocket 72 do not move together with the rotating shaft 62 and the valve body 63. In other words, the sprocket 72 and the rotating shaft 62 are engaged so as to be able to move relative to each other.

The valve body 63 is provided in the casing 61. The valve body 63 has a plurality of vanes 63a arranged in a circumferential direction (rotation direction). Both axial ends of the vanes 63a are fixed to a disk-shaped side plate 63b. The vanes 63a divide a plurality of chambers in the rotation direction. Each chamber is independent because it is separated by the vanes 63a. Therefore, when the valve body 63 is located in the passage space S1, it can seal the flow of pressurized gas from the mill 10 toward the bunker 21. That is, it can suppress the blowing up of the pressurized gas from the mill 10. The vertical length of the valve body 63 is shorter than the vertical length of the passage space defining portion 61a and the evacuation space defining portion 61b.
The valve body 63 is fixed to the rotary shaft 62, and therefore rotates coaxially with the rotary shaft 62 as the rotary shaft 62 rotates.

In addition, a seal gas is supplied to the evacuation space S2 from the seal gas supply pipe 70. The seal gas is supplied to the evacuation space S2 from the side wall opposite the passage space S1, and as shown by arrow A, flows between the valve body 63 and the inner peripheral surface of the evacuation space defining portion 61b, and is guided to the passage space S1. By supplying the seal gas in this manner, it is possible to make it difficult for solid fuel flowing through the passage space S1 to enter the evacuation space S2. In addition, solid fuel present in the evacuation space S2 can be discharged to the passage space S1.

The rotary valve 60 is also provided with a detection means for detecting the axial position of the valve body 63. The detection means includes, for example, a first switch 75 arranged in the passage space S1 and a second switch 76 arranged in the evacuation space S2. The first switch 75 is provided at a position where it comes into contact with the valve body 63 when the valve body 63 is located in the passage space S1. That is, the detection means determines that the valve body 63 is located in the passage space S1 when the valve body 63 and the first switch 75 are in contact. The second switch 76 is provided at a position where it comes into contact with the valve body 63 when the valve body 63 is located in the evacuation space S2. That is, the detection means determines that the valve body 63 is located in the evacuation space S2 when the valve body 63 and the second switch 76 are in contact.
The first switch 75 and the second switch 76 may be contact-type limit switches or non-contact-type proximity switches. The top surfaces of the first switch 75 and the second switch 76 may be inclined with respect to the horizontal plane so that solid fuel does not accumulate on the first switch 75 and the second switch 76. The detection means may be a sensor that integrally determines the amount of operation of the cylinder 73.

In this embodiment, when the valve body 63 is located in the passage space S1 (as shown by the two-dot chain line), it prevents the pressurized gas from blowing through from the mill 10. Furthermore, when the valve body 63 is located in the evacuation space S2, a part of the rotating shaft 62 is located in the passage space S1. As a result, a part of the rotating shaft 62 comes into contact with the solid fuel. For this reason, it is desirable to take measures against wear of the rotating shaft 62, such as hardening the surface of the rotating shaft 62 or installing a cover on the surface of the rotating shaft 62.

Next, the behavior of the rotary valve according to this embodiment will be described.
In this embodiment, when biomass fuel is supplied to the mill 10 as the solid fuel, the valve body 63 is disposed in the passage space S1. When coal is supplied to the mill 10 as the solid fuel, the valve body 63 is disposed in the evacuation space S2.
Therefore, when the solid fuel supplied to the mill 10 is switched from biomass fuel to coal, the valve body 63 is moved from the passage space S1 to the evacuation space S2 (evacuation process). Also, when the solid fuel supplied to the mill 10 is switched from coal to biomass fuel, the valve body 63 is moved from the evacuation space S2 to the passage space S1 (installation process).

The timing for moving the valve body 63 will be described in detail with reference to FIG.
First, in a state where coal is being supplied to the bunker 21, the valve body 63 is located in the evacuation space S2. When the introduction of biomass fuel into the bunker 21 starts at the timing t1, the timing (t3) at which the biomass fuel reaches the rotary valve 60 is calculated from the remaining amount of coal inside the bunker 21 and the coal consumption rate. When the timing (t3) at which the biomass fuel reaches the rotary valve 60 is calculated, the valve body 63 moves to the passage space S1 at the timing t2, which is earlier than t3. The timing earlier than t3 is, for example, a timing earlier than t3 that takes into consideration a timing calculation error (due to a measurement error in the remaining amount of coal or a fluctuation in the coal consumption rate) and the time for moving the valve body 63.
Next, when the loading of coal into the bunker 21 starts at the timing t4, the timing (t5) at which the coal reaches the rotary valve 60 is calculated from the remaining amount of biomass fuel inside the bunker 21 and the biomass fuel consumption rate. When the timing (t5) at which the coal reaches the rotary valve 60 is calculated, the valve body 63 is moved to the evacuation space S2 at the timing t6, which is a timing later than t5. A timing later than t5 is, for example, a timing later than t5 that takes into consideration an error in the timing calculation (due to a measurement error in the remaining amount of biomass fuel or a fluctuation in the biomass fuel consumption rate) and the time required for the movement of the valve body 63.

After the valve body 63 is moved into the evacuation space S2, the rotating shaft 62 and the valve body 63 may continue to rotate, or may be stopped. When rotating, the wear of the rotating shaft 62 left in the passage space S1 can be made uniform in the circumferential direction, and local wear can be prevented. In addition, the rotation of the valve body 63 can prevent solid fuel from entering the gap between the valve body 63 located in the evacuation space S2 and the evacuation space defining portion 61b, which would cause the solid fuel to stick. On the other hand, when the rotating shaft 62 and the valve body 63 are stopped, the power consumption can be reduced. Therefore, the selection may be made taking into consideration the wear of the solid fuel, power margin, etc.

The valve body 63 may be moved while rotating the valve body 63, or after stopping the rotation of the valve body 63. When stopping the rotation of the valve body 63, the mill 10 must be stopped temporarily. However, the time the mill 10 is stopped is shorter than when the rotary valve is removed and attached, so that it is possible to suppress a decrease in the amount of power generated by the power plant 1, or to reduce the cost of alternative fuels (such as heavy oil) used to ensure the amount of power generated.

This embodiment provides the following advantageous effects.
In this embodiment, the valve body 63 is movable between the passage space S1 and the evacuation space S2. As a result, when it is necessary to suppress the blow-through of gas from the mill 10 using the rotary valve 60, such as when a solid fuel with a relatively small pressure loss in the particle packed bed (in the downspout 24), such as biomass fuel, is supplied to the mill 10, the valve body 63 can be moved to the passage space S1 to suppress the blow-through of gas. On the other hand, when it is not necessary to suppress the blow-through of gas from the mill 10 using the rotary valve 60, such as when a solid fuel with a relatively large pressure loss in the particle packed bed (in the downspout 24), such as coal, is supplied to the mill 10, the valve body 63 can be moved to the evacuation space S2. By moving the valve body 63 to the evacuation space S2, it is possible to suppress contact between the valve body 63 and the solid fuel, and therefore it is possible to suppress wear of the valve body 63. In this way, the position of the valve body 63 can be changed according to the properties of the solid fuel, so that it is possible to suppress wear of the valve body 63 and extend the life of the valve body 63. The need for suppressing blow-by using the rotary valve 60 in the fuel supply section 17 is determined based on the relationship between the pressure loss in the particle packed bed of solid fuel supplied to the mill 10 (inside the downspout 24) and the internal pressure of the mill 10 during operation.

In addition, in this embodiment, the valve body 63 moves between the passage space S1 and the evacuation space S2 formed inside the casing 61, so that it is possible to switch between a state in which the rotary valve exerts a sealing function (a function for suppressing the blow-through of gas from the mill 10) and a state in which the valve body 63 does not come into contact with the solid fuel. Therefore, for example, switching can be performed more easily compared to a case in which switching is performed by detaching and attaching the rotary valve 60. Also, the operability of the power plant 1 can be improved. Also, since it is not necessary to detach and attach the rotary valve 60, it is possible to improve workability and work safety.

In addition, in this embodiment, the casing 61 has a passage space defining portion 61a and an evacuation space defining portion 61b. This allows the passage space S1 and the evacuation space S2 to be enclosed by the casing 61. This prevents the solid fuel from leaking out of the rotary valve 60. In addition, since the gas in the mill 10 does not flow out of the rotary valve 60, a decrease in pressure in the mill 10 can be prevented.

In addition, in this embodiment, when coal is supplied, which does not require suppression of gas blow-through, the valve body 63 is located in the evacuation space S2. This makes it possible to suppress wear of the valve body 63 due to contact with the coal. In addition, when biomass fuel is supplied, which requires suppression of gas blow-through, the valve body 63 is located in the passage space S1. This makes it possible to suppress gas blow-through.

In addition, in this embodiment, the sealing gas supply pipe 70 can supply sealing gas to the evacuation space S2. As a result, when the valve body 63 is located in the evacuation space S2, the supply of sealing gas can make it difficult for foreign matter (solid fuel, etc.) to enter between the valve body 63 and the evacuation space defining portion 61b. Also, even when the valve body 63 is located in the passage space S1, the intrusion and accumulation of foreign matter (solid fuel, etc.) in the evacuation space S2 can be suppressed.

Furthermore, in this embodiment, when the solid fuel supplied to the mill 10 is switched from biomass fuel to coal, the valve body 63 is moved from the passage space S1 to the evacuation space S2 after the coal reaches the rotary valve 60. This makes it possible to position the valve body 63 in the passage space S1 when biomass fuel is being supplied. Therefore, it is possible to more reliably suppress gas blow-through.
Furthermore, when the solid fuel supplied to the mill 10 is switched from coal to biomass fuel, the valve body 63 is moved from the evacuation space S2 to the passage space before the biomass fuel reaches the rotary valve 60. This makes it possible to position the valve body 63 in the passage space S1 when biomass fuel is being supplied. This makes it possible to more reliably suppress gas blow-by.

[Second embodiment]
Next, a second embodiment of the present disclosure will be described with reference to FIG.
This embodiment differs from the first embodiment mainly in that only the valve body slides. The same structures as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

A valve element 121 of a rotary valve 120 according to this embodiment is supported so as to be movable axially relative to a rotary shaft 122. The valve element 121 is supported so as to rotate together with the rotary shaft 122. The structure of the valve element 121 is similar to that of the valve element 63 according to the first embodiment, and therefore a detailed description thereof will be omitted.
The valve body 121 and the cylinder 73 are connected by a linear rod 123. The rod 123 and the valve body 121 are fixed to each other so as to allow rotation of the valve body 121. The rotating shaft 122 is supported by the casing 61 so as not to move in the axial direction.

In this embodiment, the rotating shaft 122 does not move in the axial direction, so the axial length of the rotating shaft 122 can be shortened. Therefore, the rotary valve 120 can be made smaller.

[Third embodiment]
Next, a third embodiment of the present disclosure will be described with reference to FIG.
The present embodiment differs from the first embodiment mainly in that the motor and the sprocket slide together with the valve body and the rotary shaft. The same structures as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

A sprocket 132 of the rotary valve 130 according to this embodiment is fixed to the rotary shaft 62. In addition, the motor 131 and the cylinder 73 are connected by a rod 134. Therefore, the driving force from the cylinder 73 is transmitted to the rotary shaft 62 via the motor 131 and the sprocket 132.
In this embodiment, the motor 131 and the sprocket 132 also move in the axial direction in conjunction with the axial movement of the rotating shaft 62 and the valve body 63. In this case, it is desirable to provide a motor rail 133 or the like that moves the motor 131 together so that the axial centers of the motor 131 and the valve body 63 do not change.

[Fourth embodiment]
Next, a fourth embodiment of the present disclosure will be described with reference to FIG.
In this embodiment, the main difference from the first embodiment is that the rotary shaft moves from the passage space to the evacuation space together with the valve body. The same structures as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

The rotary shaft 141 of the rotary valve 140 according to this embodiment protrudes slightly from the axial end of the valve body 63. Therefore, when the valve body 63 is located in the evacuation space S2, the rotary shaft 141 is not located in the passage space S1.
The passage space defining portion 61a of the casing 61 is provided with a housing portion 142 that houses the protruding portion 141a of the rotating shaft 141. The housing portion 142 supports the protruding portion 141a from below when the protruding portion 141a is housed therein (when the valve body 63 is positioned in the passage space S1).

A spring 143 is accommodated inside the accommodation section 142. A lid 144 is provided at the tip of the spring 143. The spring 143 biases the lid 144 toward the passage space S1. As a result, when the protruding portion 141a is not accommodated in the accommodation section 142, the lid 144 becomes a wall that separates the passage space S1 from the space inside the accommodation section 142. In this way, the lid 144 can suppress the intrusion of foreign matter (solid fuel) into the interior of the accommodation section 142. Therefore, it is possible to prevent the occurrence of a situation in which the protruding portion 141a cannot be accommodated due to the accumulation of foreign matter inside the accommodation section 142. In addition, a seal gas may be supplied to the interior of the accommodation section 142 through a seal gas supply pipe 145. The seal gas supply pipe 145 supplies seal gas from the back side of the accommodation section 142 toward the passage space S1. By supplying seal gas, it is possible to suppress the intrusion of foreign matter (solid fuel) into the interior of the accommodation section 142.

A pair of rails (support members) 146 that support the valve body 63 from below so that it can move in the axial direction are provided on the bottom surfaces of the passage space defining portion 61a and the evacuation space defining portion 61b. Note that, for illustration purposes, only one rail 146 is shown in FIG. 7. The pair of rails 146 extend along the axial direction. The pair of rails 146 are also arranged to sandwich a lower opening formed at the lower end of the passage space defining portion 61a.

According to this embodiment, the rotating shaft 141 is movable between the passage space S1 and the evacuation space S2. This allows the valve body 63 and the rotating shaft 141 to move to the evacuation space S2 when there is no need to suppress blow-through. This allows wear of the rotating shaft 141 as well as the valve body 63 to be suppressed.
In this embodiment, a rail 146 is provided to support the valve body 63 from below. This reduces the load acting on the rotating shaft 141 even if the rotating shaft 141 supports the valve body 63 in a cantilever manner when the rotating shaft 141 is moved to the evacuation space S2. This makes it possible to suppress damage to the rotating shaft 141 and the valve body 63.

[Fifth embodiment]
Next, a fifth embodiment of the present disclosure will be described with reference to FIG.
This embodiment differs from the first embodiment mainly in that two valve bodies are provided. The same structures as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

The rotary valve 150 of this embodiment has a first valve body 151 and a second valve body 152. The first valve body 151 and the second valve body 152 are arranged side by side in the axial direction. The first valve body 151 and the second valve body 152 are supported so as to be movable relative to the rotary shaft 141 in the axial direction. The first valve body 151 moves in the axial direction by the driving force from the first cylinder 153. The second valve body 152 moves in the axial direction by the driving force from the second cylinder 154.

The casing 155 of this embodiment has a first evacuation space defining portion 156 on one axial side of the passage space defining portion 61a. The first evacuation space defining portion 156 defines a first evacuation space S2 therein. The first valve body 151 can be retracted into the first evacuation space S2.
Further, the second valve body 152 is provided on the other axial side of the passage space defining portion 61a with a second evacuation space defining portion 157. The second evacuation space defining portion 157 defines a second evacuation space S3 therein. The second valve body 152 is capable of retracting into the second evacuation space S3.

In this embodiment, multiple valve bodies (first valve body 151 and second valve body 152) are arranged side by side in the axial direction. As a result, even if one valve body (e.g., first valve body 151) wears down and its function of suppressing gas blow-through is reduced, the other valve body (e.g., second valve body 152) can be moved to the passage space S1 to suppress blow-through with the other valve body (e.g., second valve body 152). Therefore, the life of the rotary valve 150 can be extended compared to when there is only one valve body.

Sixth Embodiment
Next, a sixth embodiment of the present disclosure will be described with reference to FIGS.
This embodiment differs from the first embodiment mainly in that the rotating shaft has a through-hole. The same structures as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

In the rotary valve 160 according to this embodiment, a rotary shaft 161 has a through-hole 162. The through-hole 162 is provided coaxially with the valve body 63.
9 and 10, the through portion 162 has a through hole 163 that penetrates in a direction intersecting the axial direction. The diameter of the through hole 163 is approximately the same as the diameter of the upstream flow passage portion 61c and the downstream flow passage portion 61d, as shown in FIG.

In addition, a rotation angle detection switch 164 is provided in the passage space S1. The rotation angle detection switch 164 detects the rotation angle of the through-hole 162. Based on the rotation angle of the through-hole 162 detected by the rotation angle detection switch 164, the rotation angle of the through-hole 162 is adjusted so that the central axis of the through-hole 163 coincides with the central axis of the upstream flow passage section 61c and the downstream flow passage section 61d. Note that the means for adjusting the rotation angle of the through-hole 162 is not limited to this. For example, the rotation angle may be adjusted by providing a rotary encoder on the rotating shaft 161, or the rotation angle may be adjusted manually. In addition, it is desirable to provide a marking indicating the central axis direction (penetration direction) of the through-hole 163 on a part that can be seen from the outside, such as the end face of the rotating shaft 161.

The casing 165 also has a storage space defining portion 166 that defines an internal space S4 that contains the through-hole 162.

The through-hole 162 and the valve body 63 are arranged side by side in the axial direction. The through-hole 162 is provided so as to be located in the passage space S1 when the valve body 63 is located in the evacuation space S2. The through-hole 162 is also provided so as to be located in the through-hole housing space S4 when the valve body 63 is located in the passage space S1.

In this embodiment, when the valve body 63 is retracted, the through portion 162 is located in the passage space S1. In addition, the through portion 162 stops the rotation of the rotating shaft 62 and the valve body 63 after the rotation angle of the through portion 162 is adjusted by the rotation angle detection switch 164 or the like so that the central axis of the through hole 163 coincides with the central axis of the upstream flow path section 61c and the downstream flow path section 61d. As a result, when the valve body 63 is retracted to the retraction space S2, the solid fuel passes through the through hole 163 of the through portion 162. This makes it possible to suppress contact between the rotating shaft 161 and the solid fuel, thereby suppressing wear of the rotating shaft 161 and accumulation of solid fuel on the rotating shaft 161.

[Seventh embodiment]
Next, a seventh embodiment of the present disclosure will be described with reference to FIG.
This embodiment differs from the first embodiment mainly in that the rotating shaft is divided. The same structures as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

A rotating shaft 171 provided in a rotary valve 170 of this embodiment has a valve body side shaft portion 172 fixed to the valve body 63 and a split shaft portion 173 that is not fixed to the valve body 63.
When the valve body 63 is retracted, the valve body side shaft portion 172 moves together with the valve body 63 to the retraction space S2 by the valve body side cylinder 174. On the other hand, when the valve body 63 is retracted, the split shaft portion 173 is pulled in the direction opposite to the retraction space S2 by the split shaft portion side cylinder 175, and is pulled out to the outside of the casing 61.

By doing this, when the valve body 63 is retracted into the evacuation space S2, the rotating shaft 171 and other parts are left behind in the passage space S1, and the remaining parts are prevented from wearing out due to contact with the solid fuel passing through the passage space S1, and solid fuel is prevented from accumulating on the rotating shaft 171.

[Eighth embodiment]
Next, an eighth embodiment of the present disclosure will be described with reference to FIG.
This embodiment differs from the first embodiment mainly in that the valve body is divided. The same structures as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

The valve body 181 provided in the rotary valve 180 according to this embodiment can be divided into a plurality of vanes 63a and a side plate 63b on the passing space S1 side. In other words, the vanes 63a and the side plate 63b on the passing space S1 side are not fixed. Furthermore, each vane 63a is twisted in one direction. In other words, the inclination direction of the vane end surface on the circumferential surface of each vane 63a is constant. Furthermore, each vane 63a is inclined so that the end on the evacuation space S2 side is forward in the direction of rotation (see A1) than the end on the passing space S1 side.

In this embodiment, when the valve body 181 is moved from the passage space S1 to the evacuation space S2, only the side plate 63b and the vanes 63a on the evacuation space S2 side are moved. That is, the valve body 181 located in the evacuation space S2 is in a state where the side plate 63b on the passage space S1 side is not present. In this state, by rotating the valve body 181 in the direction of arrow A1, the solid fuel that has entered the evacuation space S2 can be guided to the downstream fuel supply section 17b as shown by arrow A2.

The bottom surface of the evacuation space defining portion 61b may be provided with an inclined portion 182 that slopes downward toward the downstream fuel supply portion 17b. By providing the inclined portion 182, it is possible to more easily guide the solid fuel to the downstream fuel supply portion 17b.

[Ninth embodiment]
Next, a ninth embodiment of the present disclosure will be described with reference to FIG.
The present embodiment differs from the first embodiment mainly in that a partition wall is provided to separate the evacuation space S2 from the passage space S1. The same structures as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

The rotary valve 190 according to this embodiment is provided with a partition wall 191 that is movable in the axial direction. The partition wall 191 covers substantially the entire area connecting the evacuation space S2 and the passage space S1. In other words, the partition wall 191 separates the evacuation space S2 from the passage space S1.

The partition 191 is moved in the axial direction by the partition cylinder 192. By moving in the axial direction, the partition 191 can be switched between a state in which the evacuation space S2 and the passage space S1 are separated and a state in which the evacuation space S2 and the passage space S1 are connected.

A maintenance opening (opening) 193 is formed in the ceiling of the evacuation space defining portion 61b. The maintenance opening 193 is connected to the evacuation space S2. The maintenance opening 193 can be switched between an open state and a closed state by an opening/closing portion 194.

In this embodiment, the partition 191 can separate the evacuation space S2 from the passage space S1. With the valve body 63 disposed in the evacuation space S2, the partition 191 separates the evacuation space S2 from the passage space S1, making it difficult for the solid fuel and the primary air and pulverized fuel traveling from inside the mill 10 through the fuel supply unit 17 to the bunker 21 to enter the space in which the valve body 63 is disposed (the evacuation space S2). In addition, in this embodiment, a maintenance opening 193 is formed in the evacuation space defining portion 61b. This allows an operator to access the valve body 63 disposed in the evacuation space S2 through the maintenance opening 193. Therefore, maintenance can be performed on the valve body 63 disposed in the evacuation space S2.

In addition, in this embodiment, the partition wall 191 is movable in the axial direction. This allows the partition wall 191 to move simultaneously when the valve body 63 is moved from the evacuation space S2 to the passage space S1, so that the partition wall 191 does not impede the movement of the valve body 63.

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, in the above-described embodiment, an example has been described in which coal and biomass pellets are switched between being used as the solid fuel, but the solid fuel may be a biomass fuel other than biomass pellets or PC (Petroleum Coke) fuel generated during oil refining, or the like, and these solid fuels may be used in combination.
For example, in each of the above embodiments, an example has been described in which the valve body or the like is slid by a device such as a cylinder, but the present disclosure is not limited to this. For example, the valve body or the like may be slid manually.

The rotary valve, the power plant, and the method of operating the rotary valve described in the above-described embodiments can be understood, for example, as follows.
A rotary valve according to one aspect of this embodiment is provided in a solid fuel supply pipe (17) that supplies solid fuel to a crusher (10) that crushes the solid fuel, and is a rotary valve (60) that suppresses gas blow-by from the crusher (10), and includes a housing (61) that forms an outer shell, a rotating shaft (62) that is supported rotatably about a central axis (C) that extends in a direction intersecting the flow direction of the solid fuel, and a rotary valve (60) that is fixed to the rotating shaft (62) and accommodated inside the housing (61), and suppresses gas blow-by in the solid fuel supply pipe (17). and a valve body (63), the housing (61) has a passing space defining portion (61a) defining a passing space (S1) through which the solid fuel circulating in the solid fuel supply pipe (17) passes, and an evacuation space defining portion (61b) defining an evacuation space (S2) through which the solid fuel circulating in the solid fuel supply pipe (17) does not pass, the passing space (S1) and the evacuation space (S2) are aligned in a direction along the central axis (C), and the valve body (63) is movable between the passing space (S1) and the evacuation space (S2).

In the above configuration, the valve body is movable between the passage space and the evacuation space. As a result, when it is necessary to suppress the blow-through of gas from the pulverizer using the rotary valve, for example, when biomass fuel is supplied to the pulverizer, the valve body can be moved to the passage space to suppress the blow-through of gas. On the other hand, when it is not necessary to suppress the blow-through of gas from the pulverizer using the rotary valve, for example, when coal is supplied to the pulverizer, the valve body can be moved to the evacuation space. By moving the valve body to the evacuation space, contact between the valve body and the solid fuel can be suppressed, and therefore wear of the valve body can be suppressed. In this way, the position of the valve body can be changed according to the properties of the solid fuel, so that wear of the valve body can be suppressed and the life of the valve body can be extended.
In addition, in the above configuration, the valve body moves between the passage space and the evacuation space formed inside the housing, so that the rotary valve can be switched between a state where it exerts a sealing function (a function to suppress the gas from blowing through the mill) and a state where the valve body does not come into contact with the solid fuel. Therefore, it is easy to switch the solid fuel to be used.
In the above configuration, the housing has a passage space defining portion and an evacuation space defining portion. This allows the passage space and the evacuation space to be enclosed by the housing. This makes it possible to prevent the solid fuel from flowing out of the rotary valve. In addition, since the gas in the pulverizer does not flow out of the rotary valve, a decrease in pressure in the pulverizer can be suppressed.

In addition, in a rotary valve according to one aspect of this embodiment, the valve body (63) is disposed in the evacuation space (S2) when coal is supplied to the pulverizer (10) as the solid fuel, and is disposed in the passage space (S1) when biomass fuel is supplied to the pulverizer (10) as the solid fuel.

In the above configuration, when coal is supplied, which does not require suppression of gas blow-through, the valve body is placed in the evacuation space. This makes it possible to suppress wear on the valve body due to contact with the coal. Also, when biomass fuel is supplied, which requires suppression of gas blow-through, the valve body is placed in the passage space. This makes it possible to suppress gas blow-through.

In addition, in a rotary valve according to one aspect of this embodiment, the rotating shaft (62) is movable between the passage space (S1) and the evacuation space (S2).

In the above configuration, the rotating shaft is movable between the passage space and the evacuation space. This allows the valve body and the rotating shaft to be moved to the evacuation space when there is no need to suppress gas blow-through. This makes it possible to suppress wear on the valve body and the rotating shaft due to contact with solid fuel.

The rotary valve according to one aspect of this embodiment also includes a support member (146) that supports the valve body (63) from below so that the valve body (63) can move in a direction along the central axis (C).

The above configuration includes a support member that supports the valve body from below. This reduces the load acting on the rotating shaft even if the rotating shaft supports the valve body in a cantilever manner when moving the rotating shaft to the evacuation space. This makes it possible to suppress damage to the rotating shaft and the valve body.

The rotary valve according to one aspect of this embodiment has a plurality of the valve bodies (63), which are arranged in a line along the central axis (C) and are movable in the direction along the central axis (C).

In the above configuration, multiple valve bodies are arranged side by side in the direction along the central axis. As a result, even if one valve body wears out and its function of suppressing gas blow-through is reduced, the other valve bodies can be moved into the passage space to suppress gas blow-through with the other valve bodies. This makes it possible to extend the life of the rotary valve compared to a case in which there is only one valve body.

In addition, in a rotary valve according to one aspect of this embodiment, the rotating shaft (62) has a through-hole (162) in which a through-hole (163) is formed through in the direction in which the solid fuel flows, and the through-hole (162) is located in the passage space (S1) when the valve body (63) is located in the evacuation space (S2).

In the above configuration, when the valve body is located in the evacuation space, the through-hole of the rotating shaft is located in the passage space. As a result, when the valve body is being evacuated to the evacuation space, the solid fuel passes through the through hole of the through-hole. This makes it possible to suppress contact between the rotating shaft and the solid fuel, thereby suppressing wear on the rotating shaft.

The rotary valve according to one aspect of this embodiment also includes a seal gas supply unit (70) that supplies seal gas to the evacuation space (S2).

In the above configuration, the sealing gas supply unit can supply sealing gas to the evacuation space. As a result, when the valve body is located in the evacuation space, supplying sealing gas makes it difficult for foreign matter (solid fuel, etc.) to enter between the valve body and the evacuation space defining portion. Also, even when the valve body is located in the passage space, it is possible to suppress the intrusion and accumulation of foreign matter (solid fuel, etc.) in the evacuation space.

The rotary valve according to one aspect of this embodiment includes a partition wall (191) that separates the evacuation space (S2) from the passage space (S1), and the evacuation space defining portion (61b) has an opening (193) formed therein, and the partition wall (191) is movable in a direction along the central axis (C).

In the above configuration, the partition wall can separate the evacuation space from the passing space. As a result, when the valve body is disposed in the evacuation space, the partition wall separates the evacuation space from the passing space, making it difficult for the solid fuel and the gas from the pulverizer to enter the space in which the valve body is disposed. Also, in the above configuration, an opening is formed in the evacuation space defining portion. As a result, an operator can access the valve body disposed in the evacuation space through the opening. Therefore, maintenance can be performed on the valve body disposed in the evacuation space.
In addition, the partition is movable in a direction along the central axis, so that when the valve body is moved from the evacuation space to the passage space, the partition also moves at the same time, thereby preventing the partition from impeding the movement of the valve body.

The power plant according to one aspect of this embodiment includes a rotary valve (60) as described above, a pulverizer (10) to which the solid fuel is supplied via the solid fuel supply pipe (17) provided with the rotary valve (60), and a boiler (200) to which the solid fuel pulverized by the pulverizer (10) is supplied.

In addition, a method of operating a rotary valve according to one aspect of this embodiment is a method of operating a rotary valve (60) that is provided in a solid fuel supply pipe (17) that supplies solid fuel to a pulverizer (10) that pulverizes the solid fuel and that suppresses gas blow-by from the pulverizer (10), the rotary valve (60) comprising a housing (61) forming an outer shell, a rotating shaft (62) that is supported rotatably about a central axis (C) extending in a direction intersecting the flow direction of the solid fuel, and a valve body (63) that is fixed to the rotating shaft (62) and housed inside the housing (61) and suppresses gas blow-by in the solid fuel supply pipe (17), the housing (61) having a valve body (63) that is fixed to the rotating shaft (62) and housed inside the housing (61) and that suppresses gas blow-by in the solid fuel supply pipe (17), The fuel supply pipe (17) has a passage space defining portion (61a) that defines a passage space (S1) through which the solid fuel flowing in the supply pipe (17) passes, and an evacuation space defining portion (61b) that defines an evacuation space (S2) through which the solid fuel flowing in the solid fuel supply pipe (17) does not pass. The passage space (S1) and the evacuation space (S2) are aligned in a direction along the central axis (C). The valve body (63) is movable between the passage space (S1) and the evacuation space (S2). The fuel supply pipe (17) has a passage space defining portion (61a) that defines a passage space (S1) through which the solid fuel flowing in the supply pipe (17) passes, and an evacuation process that moves the valve body (63) from the passage space (S1) to the evacuation space (S2) and an installation process that moves the valve body (63) from the evacuation space (S2) to the passage space (S1).

In addition, in the method of operating the rotary valve according to one aspect of this embodiment, the evacuation process is performed when switching from a state in which biomass fuel is supplied to the pulverizer (10) as the solid fuel to a state in which coal is supplied to the pulverizer (10) as the solid fuel, and the valve body (63) is moved to the evacuation space (S2) after the coal reaches the rotary valve (60), and the installation process is performed when switching from a state in which coal is supplied to the pulverizer (10) as the solid fuel to a state in which biomass fuel is supplied to the pulverizer (10) as the solid fuel, and the valve body (63) is moved to the passage space (S1) before the biomass fuel reaches the rotary valve (60).

In the above configuration, when the solid fuel supplied to the pulverizer is switched from biomass fuel to coal, the valve element is moved from the passage space to the evacuation space after the coal reaches the rotary valve. This makes it possible to position the valve element in the passage space when biomass fuel is being supplied. This makes it possible to more reliably suppress gas blow-by.
In addition, when the solid fuel supplied to the pulverizer is switched from coal to biomass fuel, the valve element is moved from the evacuation space to the passage space before the biomass fuel reaches the rotary valve. This makes it possible to position the valve element in the passage space when biomass fuel is being supplied. This makes it possible to more reliably suppress gas blow-by.

1: Power plant 10: Mill 11: Housing 12: Grinding table 13: Grinding roller 14: Drive unit 15: Mill motor 16: Rotary classifier 16a: Blade 17: Fuel supply unit 17a: Upstream fuel supply unit 17b: Downstream fuel supply unit 17c: Supply unit flange 17d: Supply unit flange 18: Classifier motor 19: Outlet port 20: Coal feeder 21: Bunker 22: Conveyor unit 23: Coal feeder motor 24: Downspout 30: Blower unit 30a: Hot gas flow path 30b: Cold gas flow path 30c: Hot gas damper 30d: Cold gas damper 31: Primary air fan 32: Forced draft fan 34: Heat exchanger 40: Status detection unit 41: Bottom surface portion 42: Ceiling portion 45: Journal head 47 : Support arm 48 : Support shaft 49 : Pressing device 50 : Control unit 60 : Rotary valve 61 : Casing 61a : Passing space defining portion 61b : Evacuation space defining portion 61c : Upstream flow path portion 61d : Downstream flow path portion 61e : Upstream flange 61f : Downstream flange 61g : Upper bolt 61h : Lower bolt 62 : Rotating shaft 63 : Valve body 63a : Blade 63b : Side plate 70 : Seal gas supply pipe 71 : Motor 72 : Sprocket 73 : Cylinder 74 : Rod 75 : First switch 76 : Second switch 100 : Solid fuel pulverizing device 100a : Primary air flow path 100b : Pulverized fuel supply flow path 120 : Rotary valve 121 : Valve body 122 : Rotating shaft 123 : Rod 130 : Rotary valve 131 : Motor 132 : Sprocket 133 : Motor rail 134 : Rod 140 : Rotary valve 141 : Rotating shaft 141a : Protruding portion 142 : Storage portion 143 : Spring 144 : Lid 145 : Seal gas supply pipe 146 : Rail 150 : Rotary valve 151 : First valve body 152 : Second valve body 153 : First cylinder 154 : Second cylinder 155 : Casing 156 : First evacuation space defining portion 157 : Second evacuation space defining portion 160 : Rotary valve 161 : Rotating shaft 162 : Through portion 163 : Through hole 164 : Rotation angle detection switch 165 : Casing 166 : Storage space defining portion 170 : Rotary valve 171 : Rotating shaft 172 : Valve body side shaft portion 173 : Split shaft portion 174 : Valve body side cylinder 175 : Split shaft portion side cylinder 181 : Valve body 190 : Rotary valve 191 : Partition wall 192 : Partition wall cylinder 193 : Maintenance opening 194 : Opening and closing part 200 : Boiler 210 : Furnace 220 : Burner

Claims (12)

A rotary valve provided in a solid fuel supply pipe for supplying solid fuel to a pulverizer that pulverizes the solid fuel,
A housing forming an outer shell;
a rotation shaft supported rotatably about a central axis extending in a direction intersecting a flow direction of the solid fuel;
a valve body that is fixed to the rotating shaft, is housed inside the housing, and rotates about the central axis to send the solid fuel in the solid fuel supply pipe to the pulverizer and suppress the gas from blowing through the solid fuel supply pipe,
the casing has a passage space defining portion therein that defines a passage space through which the solid fuel circulating in the solid fuel supply pipe passes, and an evacuation space defining portion therein that defines an evacuation space through which the solid fuel circulating in the solid fuel supply pipe does not pass,
The passage space and the evacuation space are aligned in a direction along the central axis,
The valve body is a rotary valve that is movable between the passage space and the evacuation space. The rotary valve according to claim 1, wherein the valve body is disposed in the evacuation space when coal is supplied to the pulverizer as the solid fuel, and is disposed in the passage space when biomass fuel is supplied to the pulverizer as the solid fuel. The rotary valve according to claim 1 or 2, wherein the rotating shaft is movable between the passage space and the evacuation space. The rotary valve according to claim 3, further comprising a support member that supports the valve body from below so that the valve body can move in a direction along the central axis. The valve body is provided in a plurality of portions.
5. The rotary valve according to claim 1, wherein the valve elements are arranged side by side in a direction along the central axis and are movable in the direction along the central axis. the rotating shaft has a through-hole formed therein, the through-hole penetrating in a direction in which the solid fuel flows,
6. The rotary valve according to claim 1, wherein the through portion is located in the passage space when the valve body is located in the retract space. A rotary valve according to any one of claims 1 to 6, comprising a seal gas supply unit that supplies a seal gas to the evacuation space. A partition wall is provided to separate the evacuation space from the passage space,
An opening is formed in the evacuation space defining portion,
8. The rotary valve according to claim 1, wherein the partition wall is movable in a direction along the central axis. A rotary valve according to any one of claims 1 to 8;
a pulverizer to which the solid fuel is supplied via the solid fuel supply pipe provided with the rotary valve;
a boiler to which the solid fuel pulverized by the pulverizer is supplied. 1. A method for operating a rotary valve provided in a solid fuel supply pipe for supplying solid fuel to a pulverizer that pulverizes the solid fuel, the rotary valve suppressing gas blow-by from the pulverizer, comprising:
The rotary valve is
A housing forming an outer shell;
a rotation shaft supported rotatably about a central axis extending in a direction intersecting a flow direction of the solid fuel;
a valve body that is fixed to the rotating shaft and accommodated inside the housing and that suppresses gas from passing through the solid fuel supply pipe,
the casing has a passage space defining portion therein that defines a passage space through which the solid fuel circulating in the solid fuel supply pipe passes, and an evacuation space defining portion therein that defines an evacuation space through which the solid fuel circulating in the solid fuel supply pipe does not pass,
The passage space and the evacuation space are aligned in a direction along the central axis,
The valve body is movable between the passage space and the evacuation space,
a retracting step of moving the valve body from the passage space to the retracting space;
and an installation step of moving the valve body from the evacuation space to the passage space. The evacuation process is performed when a state in which biomass fuel is supplied to the pulverizer as the solid fuel is switched to a state in which coal is supplied to the pulverizer as the solid fuel, and after the coal reaches the rotary valve, the valve body is moved to the evacuation space,
11. The method of operating a rotary valve according to claim 10, wherein the installation process is performed when switching from a state in which the coal is supplied to the pulverizer as the solid fuel to a state in which the biomass fuel is supplied to the pulverizer as the solid fuel, and the valve body is moved to the passing space before the biomass fuel reaches the rotary valve. a solid fuel supply pipe for supplying solid fuel to the pulverizer;
a rotary valve provided in the solid fuel supply pipe;
Equipped with
The rotary valve is
A housing forming an outer shell;
a rotation shaft supported rotatably about a central axis extending in a direction intersecting a flow direction of the solid fuel;
a valve body that is fixed to the rotating shaft and accommodated inside the housing and that suppresses gas from passing through the solid fuel supply pipe;
Equipped with
the casing has a passage space defining portion therein that defines a passage space through which the solid fuel circulating in the solid fuel supply pipe passes, and an evacuation space defining portion therein that defines an evacuation space through which the solid fuel circulating in the solid fuel supply pipe does not pass,
The passage space and the evacuation space are aligned in a direction along the central axis,
The valve body is movable between the passage space and the evacuation space.
Feeding device.