Crusher and power generation plant, and method for operating the crusher

Abstract

To improve drying efficiency of solid fuel.SOLUTION: A mill 10 includes: a housing 11; a crushing table which is disposed in the housing 11 and supplied with solid fuel; a crushing roller which crushes the solid fuel on the crushing table; a carrier gas supply part which supplies a carrier gas for carrying the crushed solid fuel to the outside of the housing 11 to an interior of the housing 11; seal parts each of which seals a gap formed between a motion part and a stationary part disposed in the housing 11; a seal gas supply part 70 which supplies a seal gas, flowing into the housing 11 through the seal parts, to the seal parts; and a seal gas heating part 80 which heats the seal gas supplied by the seal gas supply part 70 during an operation of the mill 10.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a pulverizer and power plant, as well as a method of operating the pulverizer. [Background technology]

[0002] Conventionally, solid fuels (carbon-containing solid fuels) such as coal and biomass fuels are pulverized into fine powder within a predetermined 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 to a pulverizing table are pinched between the pulverizing table and a pulverizing roller to pulverize them, and fine fuels within a predetermined particle size range are selected by a classifier from the pulverized solid fuels that have been pulverized by a conveying gas (primary air) supplied from the outer periphery of the pulverizing table, and then transported to a boiler and combusted 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.

[0003] The mill is provided with a rotating device, a sliding device, etc. In the rotating and sliding parts of the rotating and sliding devices, a gap is formed between a moving part (moving body) and a stationary part (stationary body). In order to prevent the fine powder from being blown out of the mill from the gap and the fine powder from being mixed into the bearing housing, it is known to inject a seal gas into the gap (for example, Patent Document 1).

[0004] Patent Document 1 discloses a device that extracts part of the cold air from a cold air duct as sealed air and supplies it to multiple sealed air supply parts through branch pipes. Examples of the sealed air supply parts include the part where the classifier and the grinding table penetrate the mill body casing, the rotary bearing part, and the pressing jack. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-15427 Summary of the Invention [Problem to be solved by the invention]

[0006] The sealing air supplied to the mill flows into the housing partly or entirely through the gap between the moving parts and the stationary parts. Therefore, if part of the cold air from the cold air duct is supplied as sealing air as in the device of Patent Document 1, sealing gas with a lower temperature than the atmosphere inside the mill will be supplied into the mill. If sealing gas with a lower temperature than the atmosphere inside the mill is supplied into the mill, it may cause a drop in the temperature of the conveying gas inside the mill, which may deteriorate the drying efficiency of the solid fuel.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a pulverizer, a power generation plant, and a method for operating a pulverizer that can improve the drying efficiency of solid fuel. Another object of the present invention is to provide a pulverizer, a power generation plant, and a method for operating a pulverizer that can reduce the amount of seal air input. [Means for solving the problem]

[0008] In order to solve the above problems, the pulverizer, power generation plant, and pulverizer operating method of the present disclosure employ the following measures. A crusher according to one embodiment of the present disclosure comprises a housing, a crushing table disposed inside the housing and supplied with solid fuel, a crushing roller for crushing the solid fuel on the crushing table, a carrier gas supply unit for supplying a carrier gas into the inside of the housing for transporting the crushed solid fuel to the outside of the housing, a sealing unit for sealing a gap formed between a moving body and a stationary body disposed inside the housing, a sealing gas supply unit for supplying the sealing gas flowing into the inside of the housing through the sealing unit to the sealing unit, and a sealing gas heating unit for heating at least a portion of the sealing gas supplied by the sealing gas supply unit during operation.

[0009] A method for operating a crusher according to one embodiment of the present disclosure is a method for operating a crusher comprising: a casing; a crushing table disposed inside the casing and supplied with solid fuel; a crushing roller for crushing the solid fuel on the crushing table; a carrier gas supply unit for supplying a carrier gas into the inside of the casing for transporting the crushed solid fuel to the outside of the casing; a sealing unit for sealing a gap formed between a moving body and a stationary body disposed inside the casing; and a sealing gas supply unit for supplying sealing gas flowing into the inside of the casing through the sealing unit to the sealing unit, the method comprising a heating step for heating at least a portion of the sealing gas supplied by the sealing gas supply unit during operation. Effect of the Invention

[0010] According to the present disclosure, the drying efficiency of the solid fuel can be improved. In addition, the amount of seal air required can be reduced. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a configuration diagram showing a solid fuel pulverizer and a boiler according to an embodiment of the present disclosure. [Diagram 2] FIG. 1 is a longitudinal cross-sectional view of a mill according to an embodiment of the present disclosure. [Diagram 3] FIG. 2 is a schematic diagram showing a seal portion according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a configuration diagram showing a solid fuel pulverizer and a boiler according to a first embodiment of the present disclosure. [Diagram 5] FIG. 11 is a vertical cross-sectional view showing a lower portion and a seal gas heating portion of a mill according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] [First embodiment] Hereinafter, a first embodiment of a pulverizer, a power plant, and a pulverizer operating method according to the present disclosure will be described with reference to the drawings. The 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.

[0013] The solid fuel pulverizer 100 of this embodiment is an apparatus 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.

[0014] The solid fuel pulverizing device 100 of this embodiment includes a mill (pulverizing section) 10, a coal feeder (fuel supplying section) 20, a blower section (carrier gas supplying section) 30, a state detection section 40, and a control section (determination section) 50.

[0015] 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.

[0016] 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.

[0017] A drive unit 14 is provided below 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 has a table portion 12a on which the solid fuel is placed, and a connection portion 12b that connects the table portion 12a and the drive portion 14. The table portion 12a is a circular member in a plan view, and is arranged so that the lower end portion of the fuel supply portion 17 faces the table portion 12a. 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 fuel supply portion 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. The connection portion 12b is a columnar member that extends in the vertical direction and penetrates the bottom surface portion 41 of the housing 11.

[0018] 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 pulverized between the grinding table 12 and the grinding rollers 13. The pulverized solid fuel is blown upward by the carrier gas (hereinafter referred to as primary air) guided from the carrier gas passage (hereinafter referred to as primary air passage) 100a, and is guided to the rotary classifier 16. The downstream end of the primary air passage 100a is connected to the outer periphery of the housing 11 below the table portion 12a of the grinding table 12. In addition, an outlet (not shown) is provided on the outer periphery of the grinding table 12, which allows the primary air flowing in from the primary air passage 100a to flow 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 of 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, and are returned to the grinding table 12, where they are pulverized again between the grinding table 12 and the grinding roller 13.

[0019] 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 rotation center axis of the crushing table 12.

[0020] 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 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, the crushing roller 13 receives a rotational force from the crushing table 12 and rotates with 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.

[0021] A support arm 47 of the journal head 45 is supported on the side of the housing 11 by a support shaft 48 whose middle portion is aligned horizontally so that the crushing roller 13 can swing up and down about the support shaft 48. A pressing device 49 is provided on the upper end portion on the vertically upper side of the support arm 47. The pressing device 49 is fixed to the housing 11 and applies a load to the crushing roller 13 via the support arm 47 etc. so as to press the crushing roller 13 against the crushing table 12.

[0022] The drive unit 14 is a device that transmits a driving force to the grinding table 12 and rotates the grinding table 12 about its central axis. The drive unit 14 is connected to a mill motor 15 and transmits the driving force of the mill motor 15 to the grinding table 12.

[0023] 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 (hereinafter, the pulverized solid fuel is referred to as "pulverized fuel") pulverized by the pulverizing table 12 and the pulverizing rollers 13 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 the control unit 50, and rotates around the fuel supply unit 17 centering 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.

[0024] When the pulverized fuel reaches the rotary classifier 16, due to the relative balance between the centrifugal force generated by the rotation of the blades 16a and the centripetal force of the primary air flow, large diameter coarse pulverized fuel particles are knocked down by the blades 16a and returned to the pulverizing table 12 to be pulverized again, and the fine pulverized fuel is guided to the outlet port 19 in the ceiling 42 of the housing 11. The pulverized fuel classified by the rotary classifier 16 is discharged from the outlet port 19 together with the primary air into the pulverized fuel supply passage (fuel supply passage) 100b and supplied to the burner 220 of the boiler 200. When the solid fuel is coal, the pulverized fuel supply passage 100b is also called a pulverized coal pipe.

[0025] The fuel supply unit 17 is attached so that its lower end portion extends vertically into the interior of the housing 11 so as to penetrate the ceiling portion 42 of the housing 11, and supplies solid fuel input from the upper portion of the fuel supply unit 17 to the approximately central region of the grinding table 12. The fuel supply unit 17 is supplied with solid fuel from the coal feeder 20.

[0026] The coal feeder 20 includes a conveying unit 22 and a coal feeder motor 23. The conveying unit 22 is, for example, a belt conveyor, and conveys the solid fuel discharged from the lower end of the downspout 24 located directly below the bunker 21 to the top of the fuel supply unit 17 of the mill 10 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 seal 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 by, for example, the moving speed of the belt conveyor of the transport unit 22.

[0027] The blower 30 is a device that blows primary air into the housing 11 to dry the pulverized fuel and to transport it 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 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.

[0028] In this embodiment, the hot gas flow path 30a supplies a part of the air (outside air) sent out from the primary air fan 31 as hot gas 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.

[0029] 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.

[0030] 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.

[0031] 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 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 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. 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 at 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 primary air temperature at the mill inlet) and the temperature of the primary air from the space above the grinding table 12 inside the housing 11 to the outlet port 19, and controls the blower unit 30 so that the upper limit temperature is not exceeded. The upper limit temperature is determined taking into consideration the possibility of ignition of the solid fuel, etc. The primary air is cooled inside the housing 11 by transporting the pulverized fuel while drying it, and the temperature of the primary air at the outlet port 19 is, for example, about 60 to 90 degrees.

[0032] The control unit 50 is a device that controls each part of the solid fuel pulverization apparatus 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 amount of pulverized fuel circulating 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 (amount of coal supplied) 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.

[0033] The control unit 50 is composed of, for example, a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program, and the CPU reads the program into the RAM or the like and executes information processing and arithmetic processing to realize various functions. The program may be installed in a ROM or other storage medium in advance, may be provided in a state stored in a computer-readable storage medium, or may be distributed via a wired or wireless communication means. The computer-readable storage medium may be a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. The HDD may be replaced with a solid state disk (SSD) or the like.

[0034] Next, a description will be given of the boiler 200 which generates steam by performing combustion using the pulverized fuel supplied from the solid fuel pulverizer 100. The boiler 200 includes a furnace 210 and a burner 220.

[0035] 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 by a heat exchanger 34. The pulverized fuel is burned in the furnace 210, and the high-temperature combustion gas is discharged to the outside of the boiler 200 after passing through heat exchangers (not shown) such as an evaporator, a superheater, and a coal economizer.

[0036] An additional air injection port (not shown) for branching off a portion of the secondary air and injecting it into the boiler 200 may be provided above the burner 220. This forms a reduction region between the burner 220 and the additional air injection port in the boiler 200, thereby reducing NOx generated near the burner 220, thereby making it possible to reduce the NOx concentration in the combustion gas discharged from the boiler 200.

[0037] The combustion gas discharged from the boiler 200 flows through the flue 36. The combustion gas flowing through the flue 36 is subjected to a predetermined treatment in an environmental device (such as a denitration device 35 or an electric dust collector (not shown). The denitration device 35 supplies a reducing agent having an effect of reducing nitrogen oxides, such as ammonia or urea water, into a flow path through which the combustion gas flows, and promotes a reaction between the nitrogen oxides in the combustion gas to which the reducing agent has been supplied and the reducing agent by the catalytic action of a denitration catalyst installed in the denitration device 35, thereby removing and reducing the nitrogen oxides in the combustion gas. The combustion gas that has been subjected to the predetermined treatment is subjected to heat exchange between air sent out from a primary air fan 31 and air sent out from a forced draft fan 32 in a heat exchanger 34 such as an air preheater, and is led 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 and 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 power generation section, a steam turbine (not shown), 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.

[0038] The flow rate of air supplied to the boiler 200 is the sum of the primary air supplied from the PAF 31 and the secondary air supplied from the seal gas and FDF 32, and the flow rate is controlled to match the oxygen concentration in the boiler exhaust gas set according to the load of the boiler 200. In other words, when the load of the boiler 200 is the same, if the flow rate of the seal gas increases, the combined flow rate of the primary air and secondary air decreases.

[0039] Next, the sealing unit 60, the sealing gas supply unit 70, and the sealing gas heating unit 80 according to this embodiment will be described in detail with reference to FIGS. 2 to 4. FIG.

[0040] The mill 10 comprises moving parts (moving bodies) that rotate and move linearly, and fixed stationary parts (stationary bodies). Gaps are formed between the moving parts and the stationary parts to allow the movement of the moving parts. The mill 10 is provided with seal units 60 at multiple locations to seal the gaps so that the gas and pulverized fuel in the housing 11 do not leak from the gaps. A seal gas is supplied to the seal units 60 from a seal gas supply unit 70.

[0041] 2, the seal portion 60 is provided so as to seal the gap between the crushing roller 13 (moving part) and the journal shaft portion 44 (stationary part) that rotatably supports the crushing roller 13. Therefore, a seal gas is supplied to the gap formed between the crushing roller 13 and the journal shaft portion 44 (see S1).

[0042] The seal portion 60 is provided to seal the gap between the housing 11 (stationary part) and the portion of the rotary classifier 16 (moving part) that penetrates the housing 11, and the gap between the rotary classifier 16 and the fuel supply portion 17 (stationary part). Therefore, a seal gas is supplied between the housing 11 and the rotary classifier 16 (see S2). Also, a seal gas is supplied between the rotary classifier 16 and the fuel supply portion 17 (see S3).

[0043] The seal portion 60 is provided so as to seal the gap between the pressing portion (moving body) of the pressing device 49 and a cylinder (stationary body) that slidably accommodates the pressing portion. Therefore, a seal gas is supplied between the pressing portion and the cylinder (see S4).

[0044] Further, the seal portion 60 is provided so as to seal the gap between the housing 11 (stationary part) and the connection portion 12b (moving part) of the grinding table 12. Seal gas is supplied between the housing 11 and the connection portion 12b (see S5).

[0045] Next, an example of the structure of the seal portion 60 will be described. As shown in Fig. 3, the seal unit 60 supplies a seal gas to the gap G formed between the moving part and the stationary part. Note that Fig. 3 shows, as an example, the seal unit 60 that seals the gap between the housing 11 and the connection part 12b of the grinding table 12. The seal portion 60 has a space forming portion 61 provided in a stationary component. The space forming portion 61 forms a seal gas supply space 62 filled with a seal gas. A gap G is connected to the seal gas supply space 62. In detail, a gap G1 having a downstream end connected to the internal space of the housing 11 and a gap G2 having a downstream end connected to the external space of the housing 11 are connected to the seal gas supply space 62.

[0046] A seal gas is supplied from the seal gas supply unit 70 into the seal gas supply space 62. The pressure in the seal gas supply space 62 is higher than the pressure in the housing 11. As a result, approximately half of the seal gas supplied into the seal gas supply space 62 flows into the housing 11 through the gap G1 as shown by the arrow A4. In this way, the gap G is sealed so that the gas, pulverized fuel, and solid fuel in the housing 11 do not leak to the outside of the housing 11 through the gap G. The remaining half of the seal gas supplied into the seal gas supply space 62 is discharged to the outside of the housing 11 through the gap G2 as shown by the arrow A3. The upstream end of a seal gas discharge pipe (not shown) is connected to the gap G2. The downstream end of the seal gas discharge pipe is disposed in, for example, a predetermined space. That is, the seal gas discharge pipe leads the seal gas discharged from the gap G2 to the predetermined space. An example of the predetermined space is a space that workers cannot enter.

[0047] There are also cases where the entire amount of the seal gas flows into the housing 11. For example, as shown in Fig. 2, the entire amount of the seal gas supplied to the gap between the grinding roller 13 and the journal shaft portion 44 flows into the housing 11. That is, in this case, both the gap G1 and the gap G2 are connected to the internal space of the housing 11.

[0048] A seal gas is supplied to the seal portion 60 by a seal gas supply portion 70. The seal gas supply portion 70 includes a seal gas pipe 71 branched off from the cold gas flow passage 30b, and a seal gas fan 72 provided in the seal gas pipe 71, as shown in Figs. The upstream end of the seal gas pipe 71 is connected to the cold gas passage 30b upstream of the cold gas damper 30d. The downstream end of the seal gas pipe 71 is connected to the seal unit 60 provided in the mill 10. Note that in Figs. 1 and 4, the downstream end of the seal gas pipe 71 is illustrated as being connected to the bottom surface portion 41 of the housing 11 of the mill 10, which indicates that the downstream end of the seal gas pipe 71 is connected to the seal unit 60 provided in the mill 10. The downstream end of the seal gas pipe 71 is connected to all or some of the seal units 60 described above.

[0049] As shown in Figs. 1 and 4, a seal gas heating section 80 is provided at a midway position of the seal gas pipe 71. As shown in Fig. 4, the seal gas heating section 80 has an in-housing heat exchange section (in-housing heat exchange section) 81. The in-housing heat exchange section 81 is, for example, a pipe-shaped member, and the seal gas flows inside. The in-housing heat exchange section 81 is disposed inside the housing 11. In detail, the in-housing heat exchange section 81 is disposed below the table section 12a of the grinding table 12. The in-housing heat exchange section 81 heats the seal gas by exchanging heat between the seal gas flowing inside and the carrier gas flowing into the housing 11 from the primary air flow path 100a. The seal gas is heated by the seal gas heating unit 80 during normal operation of the mill 10. Normal operation of the mill 10 refers to a state in which the mill 10 is operating to grind solid fuel, or is performing a start-up or stop operation for grinding solid fuel. In other words, it refers to a state in which the grinding table 12 of the mill 10 is rotating.

[0050] According to this embodiment, the following advantageous effects are obtained. In this embodiment, a seal gas heating section 80 is provided for heating the seal gas. The seal gas is heated by heat exchange in the seal gas heating section 80 and then supplied to the seal section 60, and flows into the housing 11. This makes it possible to increase the temperature of the seal gas flowing into the housing 11. Therefore, it is possible to suppress a decrease in the temperature of the carrier gas flowing through the housing 11, thereby improving the drying efficiency of the solid fuel.

[0051] Furthermore, in this embodiment, the seal gas supplied to the seal portion 60 is heated. This causes the seal gas supplied to the seal portion 60 to expand. Therefore, the seal portion 60 can be sealed with a smaller mass flow rate of the seal gas. This makes it possible to suppress the flow rate of the seal gas supplied to the seal portion 60. As a result, the seal gas fan 72 for supplying the seal gas can be made smaller. Furthermore, the energy consumption of the seal gas fan 72 can be reduced.

[0052] The effect of suppressing the decrease in the temperature of the carrier gas will be described in detail with reference to FIG. 3. As shown by the arrow A1 in FIG. 3, the seal gas flowing through the seal gas pipe 71 is supplied to the seal gas heating section 80. The seal gas supplied to the seal gas heating section 80 is heated by heat exchange with the carrier gas. The heated seal gas is supplied to the seal section 60 as shown by the arrow A2. Half of the seal gas supplied to the seal section 60 is discharged to the outside of the housing 11 through the gap G2 as shown by the arrow A3. The temperature of the seal gas at this time is also set to the same temperature as the seal gas supplied to the seal section 60. The remaining half of the seal gas supplied to the seal section 60 is led to the inside of the housing 11 through the gap G1 as shown by the arrow A4. The temperature of the seal gas at this time is also set to the same degree as the seal gas supplied to the seal section 60.

[0053] Meanwhile, the carrier gas introduced into the housing 11 reaches the seal gas heating section 80 as shown by arrow A5. In the seal gas heating section 80, the carrier gas is cooled by exchanging heat with the seal gas. In addition, the carrier gas (see arrow A6) cooled by exchanging heat with the seal gas is mixed with the seal gas (see arrow A4) led into the inside of the housing 11 through the gap G1, and is cooled again. This is because in the seal gas heating section 80, the seal gas is not heated to a temperature equivalent to that of the carrier gas, and the temperature of the seal gas discharged from the seal gas heating section 80 is lower than that of the carrier gas.

[0054] The temperature of the conveying gas mixed with the seal gas (see arrow A7) is higher than that of the conveying gas mixed with the seal gas in the absence of the seal gas heating unit 80. This is because the provision of the seal gas heating unit 80 makes it possible to suppress the flow rate of the seal gas supplied to the sealing unit 60 as described above, thereby reducing the amount of seal gas mixed with the conveying gas (arrow A4 in FIG. 3). In other words, the amount of mixed seal gas, which is a factor in lowering the temperature of the conveying gas, can be reduced.

[0055] When the mill 10 is operated at a partial load below the rated capacity, the flow rate of the conveying gas is reduced. On the other hand, a constant flow rate of the seal gas is required regardless of the load, so the ratio of the flow rate of the seal gas to the conveying gas increases. Therefore, the effect of suppressing the decrease in the temperature of the conveying gas caused by heating the seal gas can be more effectively obtained.

[0056] In this embodiment, the in-housing heat exchanger 81 disposed inside the housing 11 exchanges heat between the seal gas and the carrier gas. This makes it possible to heat the seal gas by the carrier gas. In addition, since the seal gas is heated using the heat of the carrier gas, the energy efficiency of the entire power plant 1 can be improved compared to the case where a separate heating device (e.g., a heater) is used to heat the seal gas.

[0057] In addition, in this embodiment, since the seal gas heating section 80 is disposed below the table section 12a of the grinding table 12, heat exchange can be performed between the conveying gas and the seal gas immediately after it is supplied into the housing 11. This allows the seal gas to be heated by the conveying gas, which has a high temperature. Therefore, the seal gas can be heated effectively.

[0058] In addition, in this embodiment, a seal gas exhaust pipe is provided to guide the seal gas to be exhausted to the outside of the housing 11. This prevents the heated seal gas from being directly exhausted to the outside from the housing 11, thereby reducing the risk of contact between the seal gas and workers, etc., and thus improving safety. In addition, since the seal gas is not discharged directly from the housing 11, the blowing noise of the seal gas can be reduced.

[0059] In addition, in this embodiment, the flow rate of the sealing gas can be suppressed, so that the increase in the flow rate of the mixed fluid of the carrier gas and the sealing gas flowing through the pulverized fuel supply passage 100b can be suppressed. Since the flow passage cross-sectional area of ​​the pulverized fuel supply passage 100b is constant, the flow rate increases when the flow rate of the mixed fluid flowing through the passage increases. However, in this embodiment, the increase in the flow rate of the mixed fluid can be suppressed, so that the increase in the flow rate can be suppressed. Therefore, the wear of the inner surface of the pulverized fuel supply passage 100b caused by the pulverized fuel carried by the carrier gas can be suppressed. Therefore, the damage to the pulverized fuel supply passage 100b can be suppressed, so that the life of the pulverized fuel supply passage 100b can be extended.

[0060] In addition, in this embodiment, since the flow rate of the seal gas can be suppressed, the increase in the flow rate of the mixed fluid of the carrier gas (primary air) and the seal gas flowing in the pulverized fuel supply passage 100b can be suppressed. When the flow rate of the mixed fluid flowing in the pulverized fuel supply passage 100b increases, the flow rate ratio of the secondary air supplied to the burner 220 and the additional air supplied to the upper part of the burner 220 decreases accordingly. In this case, the supply balance of air required for suitable combustion in the burner 220 (flow rate ratio of the primary air, secondary air, and additional air) is lost, and the NOx concentration in the combustion gas and the unburned carbon content in the combustion ash may increase. For example, if NOx increases, the denitrification device 35 arranged downstream of the boiler 200 may increase the consumption of ammonia for reducing NOx in the combustion gas, and the operating cost of the power plant 1 may increase. On the other hand, in this embodiment, since the flow rate of the seal gas can be suppressed, the increase in the flow rate of the mixed fluid of the carrier gas (primary air) and the seal gas flowing in the pulverized fuel supply passage 100b can be suppressed. This ensures a balanced supply of air necessary for favorable combustion in the burner 220, and can suppress an increase in the NOx concentration in the combustion gas and an increase in the amount of unburned carbon in the combustion ash. Therefore, in the denitrification device 35, an increase in the consumption of a reducing agent (e.g., ammonia, etc.) for reducing NOx in the combustion gas can be suppressed, and an increase in the operating cost of the power plant 1 can be suppressed.

[0061] [Variation 1] The seal gas heating section 80 may have a bypass pipe 82 as shown by a dashed line in FIG. 4. The bypass pipe 82 is provided in the seal gas pipe 71 so as to bypass the in-housing heat exchange section 81. The bypass pipe 82 is provided with a flow rate control valve (not shown). The flow rate control valve can adjust the flow rate of the seal gas flowing through the bypass pipe 82 by adjusting the opening degree. The flow rate control valve can set the opening degree to zero (fully closed state). That is, the flow rate control valve can adjust the heating degree of the seal gas by adjusting the flow rate of the seal gas guided to the in-housing heat exchange section 81 and the flow rate of the seal gas bypassing the in-housing heat exchange section 81. That is, the bypass pipe 82 and the flow rate control valve function as an adjustment means for adjusting the heating degree of the seal gas.

[0062] The seal gas pipe 71 is provided with a temperature detection section 83 (detection section) downstream of the seal gas heating section 80 for detecting the temperature of the seal gas flowing inside.

[0063] The control unit 50 also has an opening control unit (not shown) that controls the opening of the flow rate control valve based on the temperature of the seal gas detected by the temperature detection unit 83. The opening control unit controls the opening of the flow rate control valve to adjust the temperature of the seal gas supplied to the seal unit 60. Specifically, for example, when the temperature of the outside air is low, such as in winter, and the temperature of the seal gas is lower than a predetermined temperature, the opening control unit controls the adjustment means to increase the temperature of the seal gas. That is, the opening of the flow rate control valve is reduced to increase the amount of the seal gas supplied to the heat exchange unit 81 inside the housing. The opening control unit may also control the adjustment means to decrease the temperature of the seal gas when the temperature of the outside air is high, such as in summer, and the temperature of the seal gas is higher than a predetermined temperature (for example, the allowable heat resistance temperature of the material used in the seal unit 60). That is, the opening of the flow rate control valve is increased to increase the amount of the seal gas bypassing the heat exchange unit 81 inside the housing. The above control is merely an example, and the control performed by the opening control unit may be other control. In addition, multiple combinations of in-housing heat exchange sections 81 and adjustment means may be arranged in series, and the degree of heating of the sealing gas may be adjusted by changing the number and distance of the in-housing heat exchange sections 81 through which the sealing gas passes, i.e., the heat transfer area of ​​the sealing gas heating section 80.

[0064] According to this modification, the heating degree of the seal gas is adjusted based on the temperature of the supplied seal gas, so that the seal gas can be supplied at a desired temperature.

[0065] [Variation 2] The seal gas heating unit 80 is not limited to the above description. For example, the seal gas heating unit 80 may have a heat exchanger 84 in the hot gas flow path arranged in the hot gas flow path 30a as shown in FIG. 4. The heat exchanger 84 in the hot gas flow path is provided downstream of the heat exchanger 34 and upstream of the hot gas damper 30c. The heat exchanger 84 in the hot gas flow path heats the seal gas by exchanging heat between the seal gas flowing therein and the hot gas (air heated by the heat exchanger 34) flowing in the hot gas flow path 30a.

[0066] In this modification, the seal gas is heated by heat exchange with the hot gas upstream of the heat gas damper 30c, and heat exchange is not performed between the seal gas and the carrier gas flowing into the housing 11, so that no decrease in temperature of the carrier gas occurs due to heat exchange. Therefore, compared to the above-mentioned first embodiment, the decrease in temperature of the carrier gas can be more effectively suppressed.

[0067] [Variation 3] 4, the seal gas heating section 80 may have an in-flue heat exchanger 85 disposed in the flue 36. The in-flue heat exchanger 85 is provided upstream of the denitrification device 35. The in-flue heat exchanger 85 heats the seal gas by exchanging heat between the seal gas flowing therethrough and the combustion gas (exhaust gas discharged from the boiler 200) flowing through the flue 36.

[0068] In this modified example, the sealing gas is heated by utilizing the heat of the combustion gas discharged outside the system, thereby improving the energy efficiency of the entire power plant 1 compared to cases where a separate heating device (e.g., a heater) is used to heat the sealing gas or where heat exchange with hot gas is performed. In this modification, the seal gas is heated by heat exchange with the combustion gas in the flue 36, and heat exchange is not performed between the seal gas and the carrier gas flowing into the housing 11, so that no decrease in temperature of the carrier gas occurs due to heat exchange. Therefore, compared to the above-mentioned first embodiment, it is possible to more effectively suppress the decrease in temperature of the carrier gas.

[0069] [Second embodiment] Next, a second embodiment of the present disclosure will be described with reference to FIG. This embodiment differs from the first embodiment in the configuration of the seal gas heating section 90. Since the other points are the same as those of the first embodiment, the same components are denoted by the same reference numerals and detailed description thereof is omitted. Note that the arrow A10 in Fig. 5 indicates the flow of the carrier gas (primary air) flowing in from the primary air flow path 100a. As shown in FIG. 5, the seal gas heating section 90 according to this embodiment has an inner wall portion 91 provided along the inner circumferential surface of the housing 11, and a seal gas flow passage 96 formed between the inner circumferential surface and the inner wall portion 91.

[0070] The inner wall portion 91 is provided along the entire circumferential area of ​​the inner peripheral surface of the housing 11. The inner wall portion 91 has a first wall portion 91a that faces the inner peripheral surface of the lower part of the side wall portion of the housing 11, and a second wall portion 91b that faces the bottom surface portion 41 of the housing 11. The inner wall portion 91 also has a seal opening 91c formed at a position that faces the outer peripheral surface of the connection portion 12b of the grinding table 12. The seal opening 91c is connected to the gap G1 and the gap G2. A fin 92 is provided on the surface of the inner wall portion 91 facing the grinding table 12. Moreover, the seal gas flow passage 96 has a labyrinth structure due to a plate portion 93 that protrudes into the flow passage.

[0071] A supply opening 94 to which the downstream end of the seal gas pipe 71 is connected is formed in the housing 11 facing the first wall portion 91a. The seal gas flows into a seal gas flow passage 96 through the supply opening 94. A discharge opening 95 through which the seal gas is discharged from the seal gas flow passage 96 is formed in the housing 11 facing the first wall portion 91a, and in the first wall portion 91a. The discharge opening 95 is provided above the supply opening 94. The seal gas discharged from the discharge opening 95 is led to the other seal portion 60.

[0072] In this embodiment, a part of the seal gas that flows into the seal gas flow passage 96 from the supply opening 94 flows through the seal gas flow passage 96 formed between the second wall portion 91b and the bottom surface portion 41, as shown by arrow A8, and is discharged from the seal opening 91c. The seal gas discharged from the seal opening 91c seals the gap between the housing 11 and the connection portion 12b of the grinding table 12. Meanwhile, a part of the seal gas that flows into the seal gas flow passage 96 from the supply opening 94 flows through the seal gas flow passage 96 formed between the first wall portion 91a and the housing 11, as shown by arrow A9, and is discharged from the discharge opening 95.

[0073] According to this embodiment, the following advantageous effects are obtained. In this embodiment, the seal gas flowing through the seal gas flow passage 96 exchanges heat with the carrier gas in the housing 11 via the inner wall portion 91. This allows the seal gas to be heated. On the other hand, by providing the seal gas flow passage 96, the high-temperature carrier gas does not come into direct contact with the inner peripheral surface of the housing 11. Therefore, damage to the housing 11 due to heat can be reduced compared to a case in which the seal gas flow passage 96 is not provided. In particular, it is possible to mitigate the reduction in strength, fatigue, and thermal stress of the housing 11.

[0074] In addition, since the sealing gas is heated by utilizing the heat dissipated to the outside through the housing 11, the energy efficiency of the entire power plant 1 can be improved compared to a case where a separate heating device (e.g., a heater) is used to heat the sealing gas.

[0075] 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, a mill according to the present disclosure is used, but the solid fuel may be a solid fuel such as biomass fuel or PC (Petroleum Coke) fuel generated during oil refining, or a mixture of these solid fuels may be used.

[0076] In addition, for example, in the above-mentioned first embodiment and modified example, the seal gas heating section 80 has one of the in-housing heat exchange section 81, the in-housing heat exchange section 84 in the hot gas flow path, and the in-flue heat exchange section 85, but the present disclosure is not limited thereto. For example, the seal gas heating section 80 may have any two of the in-housing heat exchange section 81, the in-housing heat exchange section 84 in the hot gas flow path, and the in-flue heat exchange section 85, or may have all three.

[0077] In the first embodiment, an example in which the seal gas heated by the seal gas heating unit 80 is supplied to all the seal parts 60 has been described, but the present disclosure is not limited thereto. For example, the seal gas heated by the seal gas heating unit 80 may be supplied to only some of the seal parts 60. Specifically, the heated seal gas may be supplied to the seal parts 60 other than the seal parts 60 provided in the gap formed between the crushing roller 13 and the journal shaft part 44. Rubber for oil seal is present in the vicinity of the gap formed between the crushing roller 13 and the journal shaft part 44. The rubber for oil seal is easily damaged by heat. Therefore, by not supplying the heated seal gas to the seal parts 60 provided in the gap, damage to the rubber for oil seal due to heat can be suppressed. In addition, the temperature constraint of the seal gas is relaxed for the seal parts 60 to which the heated seal gas is supplied, so that the degree of heating of the seal gas can be increased.

[0078] Moreover, the mill 10 may include both the seal gas heating section 80 of the first embodiment and the seal gas heating section 90 of the second embodiment.

[0079] The pulverizer, the power generation plant, and the method of operating the pulverizer described in the above-described embodiments can be understood, for example, as follows. A crusher according to one embodiment of the present disclosure includes a housing (11), a crushing table (12) disposed inside the housing (11) and supplied with solid fuel, a crushing roller (13) for crushing the solid fuel on the crushing table (12), a carrier gas supply unit (30) for supplying a carrier gas to the inside of the housing (11) for transporting the crushed solid fuel to the outside of the housing (11), a sealing unit (60) for sealing a gap formed between a moving body and a stationary body disposed inside the housing (11), a sealing gas supply unit (70) for supplying the sealing gas flowing into the inside of the housing (11) through the sealing unit (60) to the sealing unit (60), and a sealing gas heating unit (80) for heating at least a portion of the sealing gas supplied by the sealing gas supply unit (70) during operation.

[0080] The above-mentioned configuration includes a seal gas heating section that heats the seal gas. The supplied seal gas flows into the housing. This makes it possible to increase the temperature of the seal gas flowing into the housing. This makes it possible to suppress a decrease in the temperature of the carrier gas flowing through the housing, thereby improving the drying efficiency of the solid fuel. In addition, in the above configuration, the sealing gas supplied to the sealing portion is heated. This causes the sealing gas to expand. Therefore, sealing can be achieved with a smaller mass flow rate of the sealing gas. This allows the flow rate of the sealing gas to be suppressed. As a result, the size of a device for supplying the sealing gas (e.g., a blower) can be reduced. Also, the energy consumption of the device for supplying the sealing gas can be reduced. Also, an increase in the flow rate of the mixed fluid of the carrier gas and the sealing gas flowing through the pulverized fuel supply passage (100b) can be suppressed. This ensures a supply balance of air necessary for suitable combustion in the burner (220), and suppresses an increase in the NOx concentration in the combustion gas and an increase in the unburned carbon content in the combustion ash.

[0081] In addition, in a pulverizer according to one embodiment of the present disclosure, the seal gas heating section (80) has an internal heat exchange section (81) that is disposed inside the housing (11) and exchanges heat between the seal gas and the conveying gas in the housing (11).

[0082] In the above-described configuration, the housing internal heat exchanger disposed inside the housing exchanges heat between the seal gas and the carrier gas, thereby making it possible to heat the seal gas by the carrier gas. In addition, since the seal gas is heated using the heat of the conveying gas, the energy efficiency of the entire power plant (1) can be improved compared to a case where a separate heating device (e.g., a heater) is used to heat the seal gas.

[0083] In addition, in a pulverizer according to one embodiment of the present disclosure, the conveying gas supply unit (30) supplies the conveying gas to a lower part of the housing (11), and the housing internal heat exchange unit (81) is arranged in a lower part within the housing (11).

[0084] In the above configuration, heat exchange can be performed between the carrier gas and the seal gas immediately after it is supplied to the inside of the housing. This allows the seal gas to be heated by the carrier gas, which has a high temperature. Therefore, the seal gas can be heated effectively.

[0085] In addition, in a pulverizer according to one embodiment of the present disclosure, the conveying gas supply section (30) has a cold gas flow path (30b) and a hot gas flow path (30a) through which a hot gas having a higher temperature than the gas flowing through the cold gas flow path (30b) flows, and the seal gas heating section (80) has a heat exchange section (84) in the hot gas flow path that is disposed inside the hot gas flow path (30a) and exchanges heat between the seal gas and the hot gas.

[0086] In the above-described configuration, the heat exchanger in the hot gas flow path arranged inside the hot gas flow path exchanges heat between the seal gas and the hot gas, whereby the seal gas can be heated by the hot gas. In addition, since the heat of the hot gas is used to heat the seal gas, the energy efficiency of the entire power plant can be improved compared to when a separate heating device (e.g., a heater) is used to heat the seal gas.

[0087] In addition, in a pulverizer according to one embodiment of the present disclosure, the seal gas heating section (80) has an inner wall section (91) provided along an inner circumferential surface of the housing (11), and a seal gas flow path (96) formed between the inner circumferential surface and the inner wall section (91).

[0088] In the above configuration, the seal gas flowing through the seal gas flow passage exchanges heat with the gas (carrier gas) inside the housing through the inner wall. This allows the seal gas to be heated. Meanwhile, by providing the seal gas flow passage, the temperature of the gas inside the housing that contacts the inner peripheral surface of the housing is reduced compared to when the seal gas flow passage is not provided. Therefore, damage to the housing caused by heat can be reduced. In particular, it is possible to mitigate the reduction in strength, fatigue, and thermal stress of the housing. In addition, since the sealing gas is heated using the heat dissipated to the outside through the housing, the energy efficiency of the entire power plant can be improved compared to when a separate heating device (e.g., a heater) is used to heat the sealing gas.

[0089] The crusher according to an aspect of the present disclosure further includes a seal gas discharge pipe for guiding the seal gas discharged to the outside of the housing (11).

[0090] In the above-mentioned configuration, a sealing gas exhaust pipe is provided to guide the sealing gas to be exhausted to the outside of the housing. This prevents the heated sealing gas from being directly exhausted from the housing to the outside, thereby reducing the risk of contact between the sealing gas and workers, etc., and thus improving safety. In addition, since the sealing gas is not discharged directly from the housing, the blowing noise of the sealing gas can be reduced.

[0091] In addition, a pulverizer according to one embodiment of the present disclosure includes a detection unit (83) that detects the temperature of the sealing gas supplied, and the sealing gas heating unit (80) has an adjustment means (82) that adjusts the heating degree of the sealing gas, and the temperature of the sealing gas is adjusted by the adjustment means (82) based on the temperature of the sealing gas detected by the detection unit (83).

[0092] In the above-described configuration, the heating degree of the seal gas is adjusted based on the temperature of the supplied seal gas, thereby making it possible to supply seal gas at a desired temperature. For example, when the temperature of the sealing gas is lower than a predetermined temperature, the adjustment means may be controlled to increase the temperature of the sealing gas, and when the temperature of the sealing gas is higher than the predetermined temperature, the adjustment means may be controlled to decrease the temperature of the sealing gas.

[0093] A power plant (1) according to one embodiment of the present disclosure includes a pulverizer (10) as described above, a boiler (200) that burns the solid fuel pulverized by the pulverizer (10) using a burner (220) to generate steam, a fuel supply passage (100b) that guides the solid fuel pulverized by the pulverizer (10) to the boiler by the conveying gas flowing therethrough, and a power generation unit that generates electricity using the steam generated by the boiler (200).

[0094] In the above configuration, the decrease in temperature of the conveying gas discharged from the pulverizer can be suppressed, and therefore an increase in the flow rate of the conveying gas flowing through the fuel supply flow path can be suppressed. Since the cross-sectional area of ​​the fuel supply flow path is constant, an increase in the flow rate of the conveying gas flowing through the flow path increases the flow rate of the conveying gas. However, in the above configuration, the increase in the flow rate of the conveying gas can be suppressed, and therefore an increase in the flow rate of the conveying gas can be suppressed. Therefore, wear of the fuel supply flow path caused by the pulverized solid fuel transported by the conveying gas can be suppressed. Therefore, damage to the fuel supply flow path can be suppressed, and the life of the fuel supply flow path can be extended.

[0095] Moreover, the power plant (1) according to one embodiment of the present disclosure includes a flue (36) through which the combustion gas discharged from the boiler (200) flows, and the sealing gas supply unit (70) has an intra-flue heat exchange unit (85) that is disposed in the flue (36) and exchanges heat between the sealing gas and the combustion gas.

[0096] In the above-described configuration, the flue heat exchanger disposed inside the flue exchanges heat between the seal gas and the combustion gas, thereby making it possible to heat the seal gas by the combustion gas. In addition, since the heat of the combustion gas is used to heat the sealing gas, the energy efficiency of the entire power plant can be improved compared to when a separate heating device (e.g., a heater) is used to heat the sealing gas.

[0097] In addition, a method for operating a crusher according to one embodiment of the present disclosure is a method for operating a crusher (10) including a housing (11), a crushing table (12) arranged inside the housing (11) and to which solid fuel is supplied, a crushing roller (13) for crushing the solid fuel on the crushing table (12), a conveying gas supply unit (30) for supplying a conveying gas to the inside of the housing (11) for conveying the crushed solid fuel to the outside of the housing (11), a sealing unit (60) for sealing a gap formed between a moving body and a stationary body arranged inside the housing (11), and a sealing gas supply unit (70) for supplying a sealing gas flowing into the inside of the housing (11) through the sealing unit (60) to the sealing unit (60), and includes a heating step for heating at least a portion of the sealing gas supplied by the sealing gas supply unit (70) during operation. [Explanation of symbols]

[0098] 1: Power plant 10: Mill (grinder) 11: Housing 12: Grinding table 12a: Table section 12b: Connection part 13: Crushing roller 14: Drive unit 15: Mill motor 16: Rotary classifier 16a: Blade 17:Fuel supply section 18: Classifier motor 19: Exit port 20:Coal feeding machine 21: Banka 22: Transport section 23: Coal feeder motor 24: Downspout 30: Blower section (carrier gas supply section) 30a: Hot gas flow path 30b: Cold gas passage 30c: Thermal gas damper 30d: Cold gas damper 31: Primary air ventilator 32: Forced air ventilator 34: Heat exchanger 35: Denitration equipment 36: Flue 40: Status detection unit 41: Bottom part 42: Ceiling 44: Journal shaft part 45: Journal Head 47: Support arm 48: Support shaft 49: Pressing device 50: Control section 60: Seal part 61: Space forming part 62: Seal gas supply space 70: Seal gas supply section 71: Seal gas piping 72: Seal gas fan 80: Seal gas heating section 81: Heat exchanger inside the housing (heat exchanger inside the housing) 82: Bypass piping 83: Temperature detection unit (detection unit) 84: Heat exchange section in hot gas flow path 85: Flue heat exchange section 90: Seal gas heating section 91: Inner wall 91a: First wall 91b: 2nd wall part 91c: Seal opening 92: Finn 93: Board part 94: Supply opening 95 :Discharge opening 96: Seal gas passage 100: Solid fuel crushing device 100a: Primary air flow passage 100b: Pulverized fuel supply passage 200: Boiler 210: Furnace 220: Burner

Claims

1. A housing and a grinding table disposed within the housing and supplied with solid fuel; a grinding roller for grinding the solid fuel on the grinding table; a carrier gas supply unit that supplies a carrier gas to the inside of the housing so as to carry the pulverized solid fuel to the outside of the housing; a seal portion that seals a gap formed between a moving body and a stationary body disposed inside the housing; a seal gas supply unit that supplies the seal gas flowing into the housing through the seal unit to the seal unit; a seal gas heating section that heats at least a portion of the seal gas supplied by the seal gas supply section during operation.

2. 2. The pulverizer according to claim 1, wherein the seal gas heating section includes an internal heat exchange section disposed inside the housing and exchanging heat between the seal gas and the conveying gas inside the housing.

3. the carrier gas supply unit supplies the carrier gas to a lower portion of the housing, The pulverizer according to claim 2 , wherein the housing internal heat exchanger is disposed in a lower portion inside the housing.

4. The carrier gas supply unit has a cold gas flow path and a hot gas flow path through which a hot gas having a higher temperature than the gas flowing through the cold gas flow path flows, 4. The pulverizer according to claim 1, wherein the seal gas heating section includes a heat exchange section in the hot gas flow passage that is disposed inside the hot gas flow passage and exchanges heat between the seal gas and the hot gas.

5. 5. A pulverizer according to claim 1, wherein the seal gas heating section has an inner wall section provided along an inner circumferential surface of the housing, and a seal gas flow path formed between the inner circumferential surface and the inner wall section.

6. 6. The crusher according to claim 1, further comprising a seal gas exhaust pipe for guiding the seal gas exhausted to the outside of the housing.

7. A detection unit is provided for detecting the temperature of the seal gas to be supplied, The seal gas heating unit has an adjustment means for adjusting the heating degree of the seal gas, 7. The crusher according to claim 1, wherein the temperature of the seal gas is adjusted by the adjusting means based on the temperature of the seal gas detected by the detector.

8. A crusher according to any one of claims 1 to 7; a boiler that generates steam by burning the solid fuel pulverized by the pulverizer with a burner; a fuel supply flow path through which the solid fuel pulverized by the pulverizer is guided to the boiler by the carrier gas flowing therethrough; a power generation unit that generates electricity using the steam generated by the boiler.

9. a flue through which the combustion gas discharged from the boiler flows; The power plant according to claim 8 , wherein the seal gas supply unit includes an in-flue heat exchange unit that is disposed in the flue and exchanges heat between the seal gas and the combustion gas.

10. A housing and a grinding table disposed within the housing and supplied with solid fuel; a grinding roller for grinding the solid fuel on the grinding table; a carrier gas supply unit that supplies a carrier gas to the inside of the housing so as to carry the pulverized solid fuel to the outside of the housing; a seal portion that seals a gap formed between a moving body and a stationary body disposed inside the housing; A seal gas supply unit that supplies a seal gas flowing into the housing through the seal unit to the seal unit, A method for operating a pulverizer, comprising the step of heating at least a portion of the seal gas supplied by the seal gas supply unit during operation.

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