JP2019037941A - Crusher and operation method of crusher - Google Patents

Abstract

To suppress abrupt combustion by injecting a fire extinguisher when the abrupt combustion occurs in a box body even in any operation state that pressure in at least the box body differs from one another.SOLUTION: A crusher 5 for crushing solid fuel to fine particle solid fuel comprises: a housing 41 for constituting a contour of the crusher 5; pressure sensors 61A, 61B for detecting pressure in the housing 41; a first extinguisher injection part 60A for injecting a fire extinguisher when the pressure detected by the pressure sensor 61A is not lower than a prescribed first threshold in a normal operation state of the crusher 5; and a second extinguisher injection part 60B for injecting a fire extinguisher when the pressure detected by the pressure sensor 61B is not lower than a second threshold which is different from the first threshold in a stop operation state of the crusher 5.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pulverizer equipped with fire extinguishing equipment and a method of operating the pulverizer.

  Solid fuels such as coal and biomass used in thermal power generation facilities are pulverized into fine powders by a pulverizer and supplied to a combustion apparatus such as a boiler. The pulverizer pulverizes solid fuel such as coal and biomass introduced from the coal supply pipe to the pulverization table by crushing between the pulverization table and the pulverization roller, and is pulverized by the carrier gas supplied from the outer periphery of the pulverization table. The finely pulverized fuel is divided into small particles with a classifier and conveyed to the combustion device.

  Biomass fuel is attracting attention as one of the measures to reduce carbon dioxide emissions such as boilers that use fossil fuel. Biomass fuel is supplied to a pulverizer in the form of pellets and is pulverized. For example, it is easy to ignite due to static electricity, which may cause rapid combustion, and may cause more rapid combustion than coal (pulverized coal). When biomass is used as fuel, safety management must be strengthened.

  Patent Document 1 discloses that when a pressure higher than the normal pressure is generated inside the mill, a number of pressure suppressors are operated, and the pulverized coal supply means, the pulverization means, and the separation means are stopped.

  In Patent Document 2, the differential pressure between the pressure along the traveling direction of the shock wave generated by the rapid combustion and the pressure in the direction perpendicular to the traveling direction is a predetermined value or more, or the internal pressure of the fine pulverizer or the hot air duct is a predetermined value or more. It is disclosed that the pulverizer is stopped when it becomes.

Japanese Patent Publication No.58-35239 JP 2002-143714 A

  Patent Document 1 and Patent Document 2 disclose that the function of the pulverizer is stopped when the pressure in the pulverizer becomes equal to or higher than a predetermined pressure. There is no description of ignition of solid fuel inside the grinder.

  The pulverizer is not only different in pressure in the pulverizer depending on the operation state (for example, normal operation state, operation stop operation state, etc.), but also when solid fuel is present in any operation state. In the pulverizer, solid fuel may ignite and rapid combustion may occur. Therefore, even if the ignition to the solid fuel is sensed only in a specific operating state and the rapid combustion is suppressed, the rapid combustion may not be suppressed in other operating states.

  The present invention has been made in view of such circumstances, and at least in any operating state where the pressure in the pulverizer is different, the fire extinguishing agent is ejected when rapid combustion occurs in the housing. It is another object of the present invention to provide a pulverizer capable of suppressing rapid combustion and a method of operating the pulverizer.

In order to solve the above problems, the pulverizer and the pulverizer operating method of the present invention employ the following means.
A pulverizer according to an aspect of the present invention is a pulverizer that pulverizes solid fuel into finely divided solid fuel, and detects a casing that forms an outer shell of the pulverizer and a pressure in the casing. A pressure sensor, and a first fire extinguishing agent jetting unit that jets a fire extinguishing agent into the housing when the pressure detected by the pressure sensor is equal to or higher than a predetermined first threshold when the pulverizer is in the first operating state; In a second operation state where the pulverizer is in an operation state different from the first operation state, when the pressure detected by the pressure sensor is equal to or greater than a second threshold value which is a threshold value different from the first threshold value, A second extinguishing agent jetting part for jetting the extinguishing agent into the housing.

Since a large amount of the pulverized solid fuel is present in the pulverizer casing, the pulverized fine powdered solid fuel may be ignited. When the pulverized solid fuel is ignited, the pressure in the housing rises higher than the pressure before rapid combustion (that is, the pressure during normal operation). For this reason, generation | occurrence | production of rapid combustion can be judged by detecting the pressure in a housing | casing.
In the above configuration, different threshold values are set as the first threshold value in the first operation state and as the second threshold value in the second operation state. Therefore, even when the pressure during normal operation differs between the first operation state and the second operation state, it is possible to determine the occurrence of rapid combustion in the housing in each operation state. In addition, different extinguishing agent ejection parts are operated in the first operation state and the second operation state. Thus, even when the fire extinguishing agent is ejected in one operating state and then the other operating state is reached, the fire extinguishing agent can be ejected when rapid combustion occurs in the other operating state. . Therefore, at least in any operating state where the pressure in the casing is different, if rapid combustion occurs in the casing, the extinguishing agent can be ejected to suppress rapid combustion.

  In the pulverizer according to an aspect of the present invention, the first operation state includes the pulverizer in a normal operation state, and the second operation state includes a time when the pulverizer is stopped and a transition to an operation stop. In the stop operation state, the first threshold value is set based on the highest pressure in the casing in the normal operation state, and the second threshold value is based on the pressure in the casing in the stop operation state. It may be set. The second threshold may be set higher than the first threshold.

In the above configuration, the first threshold value is set based on the pressure inside the casing when the pulverizer is in a normal operation state. As a result, when the pulverizer is in a normal operation state, it is possible to inject the extinguishing agent in response to the rapid combustion that has occurred in the casing, thereby suppressing the rapid combustion. In addition, since the pressure value in the housing changes in each operation state in the stop operation state, the second threshold value is set based on the highest pressure in the housing in the stop operation state of the crusher. Thereby, when the pulverizer is in the stop operation state, the fire extinguisher can be injected in response to the rapid combustion generated in the housing, and the rapid combustion can be suppressed.
Therefore, for example, in the normal operation state, rapid combustion occurs in the casing, and after the first extinguishing agent injection unit injects the extinguishing agent and suppresses rapid combustion, the operation is performed in the stop operation state in order to stop the pulverizer. In this case, even if rapid combustion occurs again in the housing, the second fire extinguishing agent injection unit injects the fire extinguishing agent, so that rapid combustion in the housing can be suppressed.
In addition, as a method of setting the first threshold value based on the pressure in the casing in the normal operation state, for example, a pressure obtained by adding a predetermined pressure to the normal pressure in the normal operation state may be set as the first threshold value. Good. Further, as a method of setting the second threshold value based on the pressure in the casing in the stop operation state, for example, as the second threshold value, a pressure obtained by adding a predetermined pressure to the normal pressure in the stop operation state may be set. Good.

  In the pulverizer according to one aspect of the present invention, the first fire extinguishing agent ejection part and the second fire extinguishing agent ejection part may be provided in pairs.

  In the said structure, the 1st fire extinguishing agent ejection part and the 2nd fire extinguishing agent ejection part are provided in pairs. Thereby, when performing installation and maintenance of the first extinguishing agent ejection part and the second extinguishing agent ejection part, the first extinguishing agent ejection part and the second extinguishing agent ejection part can be simultaneously operated. Therefore, compared with the case where a 1st fire extinguishing agent ejection part and a 2nd fire extinguishing agent ejection part are provided separately, the work burden at the time of installation can be reduced, and the work burden at the time of maintenance can also be reduced.

  The pulverizer according to an aspect of the present invention may be configured not to inject the extinguishing agent from the first extinguishing agent ejection part and / or the second extinguishing agent ejection part, depending on the type of the solid fuel.

  In the above configuration, the extinguishing agent is not injected from the first extinguishing agent ejection part and / or the second extinguishing agent ejection part depending on the type of solid fuel to be pulverized by the pulverizer. Thereby, it can be determined whether to inject a fire extinguisher into a housing | casing according to the kind of solid fuel. Therefore, for example, when the solid fuel having low ignitability is pulverized, if the extinguishing agent is not ejected from the first extinguishing agent ejection part and / or the second extinguishing agent ejection part, rapid combustion is caused in the housing. In the state where it does not occur, the pressure rises due to a factor other than rapid combustion, and the malfunction of injecting the fire extinguisher into the housing can be prevented.

  A pulverizer according to an aspect of the present invention includes a carrier gas supply pipe through which a carrier gas supplied into the casing flows, and a part of the carrier gas supply pipe has a predetermined pressure inside the carrier gas supply pipe. You may open by becoming above.

In the above configuration, a part of the carrier gas supply pipe is opened when the inside of the carrier gas supply pipe becomes a predetermined pressure or higher. As a result, when rapid combustion occurs in the housing and the pressure increase in the housing propagates into the carrier gas supply pipe, a part of the carrier gas supply pipe opens when the pressure in the carrier gas supply pipe exceeds a predetermined pressure. To do. When a part of the carrier gas supply pipe is opened, the pressure is effectively released from the opening, so that an increase in the pressure in the carrier gas supply pipe over a predetermined pressure can be suppressed. Therefore, while maintaining the pressure in the carrier gas supply pipe below a predetermined pressure, the rapid increase in the density of the pulverized solid fuel in the housing is also suppressed by suppressing the sudden rise in the pressure in the housing of the pulverizer. Can be further suppressed. Therefore, it is possible to prevent the inside of the carrier gas supply pipe from exceeding the expected pressure and damage the carrier gas supply pipe, and more effectively suppress the rapid combustion when the extinguishing agent in the casing of the pulverizer is ejected. it can.
In addition, since a part of the carrier gas supply pipe is opened, the pressure in the carrier gas supply pipe can be released without providing a new space such as a rupture disk in the carrier gas supply pipe. be able to. Therefore, space saving and cost reduction can be achieved as compared with the case where a separate device or the like is provided.

  A pulverizer operating method according to an aspect of the present invention is a pulverizer operating method for pulverizing solid fuel supplied in a casing constituting an outer shell, wherein the pressure detecting step detects the pressure in the casing. And when the pressure detected in the pressure detection step is equal to or higher than a predetermined first threshold value when the pulverizer is in the first operating state, the first extinguishing agent is ejected from the first extinguishing agent ejection part into the housing. In the first fire extinguishing agent ejection step and the second operation state in which the pulverizer is in an operation state different from the first operation state, the pressure detected in the pressure detection step is a threshold value different from the first threshold value. A second extinguishing agent ejection step for ejecting the extinguishing agent from the second extinguishing agent ejection part in the case when it is equal to or greater than two thresholds;

  According to the present invention, when rapid combustion occurs in the casing at least in any operating state where the pressure in the casing is different, the extinguishing agent can be ejected to suppress rapid combustion.

It is a schematic structure figure showing boiler equipment provided with a crusher concerning a 1st embodiment of the present invention. It is the longitudinal section showing the crusher concerning a 1st embodiment of the present invention.

Hereinafter, an embodiment of a pulverizer and a method for operating the pulverizer according to the present invention will be described with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 shows a boiler facility 1 including a pulverizer according to the present embodiment. In the present embodiment, the upper direction indicates the vertical upper direction, and the lower direction indicates the vertical lower direction.
In the present embodiment, the boiler facility 1 includes a pulverizer 5 that uses, for example, biomass fuel as the solid fuel, and pulverizes the solid fuel such as biomass fuel supplied to the boiler body 3 into a fine powder solid fuel. The pulverizer 5 may be of a type that pulverizes only biomass fuel, or may be of a type that pulverizes biomass fuel together with coal. Here, the biomass fuel is an organic resource derived from renewable organisms, for example, thinned wood, waste wood, driftwood, grass, waste, sludge, tires, and recycled fuel (pellet and Chip) and the like, and is not limited to those shown here. Biomass fuel is carbon neutral that does not emit carbon dioxide, which is a global warming gas, because carbon dioxide is taken in during the growth process of biomass, and its use has been studied in various ways.

A pulverized fuel supply pipe 7 is connected to the pulverizer 5, and the pulverized fuel pulverized by the pulverizer 5 is guided to the burner 9 through the pulverized fuel supply pipe 7 together with hot air serving as a carrier gas. ing.
Biomass fuel stored in the biomass silo 11 is guided to the pulverizer 5 via the bunker 13.
A hot air supply pipe (carrier gas supply pipe) 15 is connected to the pulverizer 5. The hot air supply pipe 15 is connected to the primary ventilator 17, and the air preheated by the air preheater 19 and the air bypassing the air preheater 19 are mixed to guide the temperature-adjusted air. It is like that. A part of the exhaust gas that has passed through the electric dust collector 23 is guided to the hot air supply pipe 15 via the gas recirculation ventilator 21. Therefore, an air-fuel mixture whose temperature is adjusted by the air preheater 19 and whose oxygen concentration is adjusted by the exhaust gas is guided to the pulverizer 5 through the hot air supply pipe 15.

  A flame is formed by the burner 9 in a furnace in the boiler body 3, and steam is generated by a heat exchanger (not shown) in the boiler body 3. The generated steam is guided to a steam turbine (not shown) to generate electric power.

The exhaust gas discharged from the boiler body 3 is denitrated by the denitration device 25, heated by the air preheater 19 from the primary ventilator 17, and then led to the electric dust collector 23. The exhaust gas is dedusted by the electrostatic precipitator 23 and then guided to the desulfurization device 29 via the induction fan 27. A part of the exhaust gas may be extracted on the upstream side of the induction fan 27 and guided to the hot air supply pipe 15 via the gas recirculation fan 21.
The exhaust gas guided from the induction ventilator 27 is desulfurized by the desulfurization device 29 and then guided to the chimney 31 to be released to the atmosphere.

  FIG. 2 shows details of the pulverizer 5 shown in FIG. The pulverizer 5 is a vertical mill, and pulverizes solid fuel such as biomass fuel into fine powder.

  A housing (housing) 41 constituting an outer shell of the pulverizer 5 has a bowl-shaped cylindrical hollow shape, and a fuel supply pipe 43 is attached to a central portion of the ceiling portion 42. The fuel supply pipe 43 supplies pellet-like biomass fuel introduced from the biomass silo 11 (see FIG. 1) into the housing 41, and extends in the vertical direction (vertical direction) to the center position of the housing 41. The lower end extends to the inside of the housing 41.

  A gantry 44 is installed on the bottom surface portion 40 of the housing 41, and a crushing table 45 is rotatably disposed on the gantry 44. The fuel supply pipe 43 is disposed so that the lower end of the crushing table 45 faces the center of the crushing table 45. The fuel supply pipe 43 supplies biomass fuel from above to below as indicated by an arrow A0.

  The crushing table 45 is rotatable about a central axis in the vertical direction (vertical direction) and is driven by a driving device (not shown). The upper surface of the crushing table 45 may have, for example, an inclined shape such that the central portion is high and decreases toward the outside, and the outer peripheral portion is curved upward.

  A plurality of crushing rollers 46 are arranged above the crushing table 45 so as to face each other. Each crushing roller 46 is arranged at equal intervals in the circumferential direction above the outer peripheral portion of the crushing table 45 (in FIG. 2, only one crushing roller 46 and its peripheral devices are shown as representatives. ). The crushing roller 46 can swing up and down and is supported so as to be able to approach and separate from the upper surface of the crushing table 45. When the pulverizing table 45 rotates in a state where the outer peripheral surface is in contact with the upper surface of the pulverizing table 45, the pulverizing roller 46 is rotated by receiving the rotational force from the pulverizing table 45. When the biomass fuel is supplied from the fuel supply pipe 43, the biomass fuel is pressed and pulverized between the pulverizing roller 46 and the pulverizing table 45.

  A scraper 48 that discharges biomass fuel and foreign matter accumulated on the bottom surface 40 of the housing 41 to the outside of the housing 41 is provided below the crushing table 45. The scraper 48 is fixed to a part of the crushing table 45 and is rotatable coaxially with the crushing table 45. A brush part 49 is provided at the tip of the scraper 48. The brush portion 49 is disposed such that the lower end thereof is in contact with the upper surface of the bottom surface portion 40 of the housing 41, and slides on the upper surface of the bottom surface portion 40. Further, a discharge opening 50 is formed on the bottom surface portion 40 of the housing 41 and on the rotation track of the brush portion 49. The discharge opening 50 communicates with a pyrite box 52 disposed outside the housing 41 via a discharge pipe 51.

  A hot air supply pipe 15 (see FIG. 1) is connected to the lower portion of the housing 41. The hot air supply pipe 15 includes a preheated air flow pipe 15b through which air preheated by the air preheater 19 flows, a cooling air flow pipe 15c through which cooling air bypassing the air preheater 19 flows, and a preheated air flow pipe 15b. A confluence 15a in which preheated air that has circulated inside and cooling air that has circulated in the cooling air circulation pipe 15c merge (mix), and a mixed air circulation pipe 15d in which the air mixed in the merging section 15a circulates. Have. The mixed air circulation pipe 15 d communicates with the housing 41. Air is supplied from the primary ventilator 17, of which preheated air heated by the air preheater 19 and cold air supplied by bypassing the air preheater 19 are supplied, and the preheated air and the cold air join together. At 15a, the hot air is controlled to have a temperature within a predetermined range. Furthermore, a part of the exhaust gas that has passed through the electric dust collector 23 is guided through the gas recirculation ventilator 21, and the oxygen concentration of the hot air is adjusted by the exhaust gas.

A part of the cooling air circulation pipe 15c is formed by, for example, a flexible expansion 47 so as to allow expansion and contraction in the extending direction of the cooling air circulation pipe 15c. Further, the expansion 47 is formed so as to break (open) when the pressure inside the hot air supply pipe 15 reaches a predetermined pressure. The predetermined pressure at which the expansion 47 breaks is set based on the pressure in the housing 41 in the normal operation state. Specifically, the heat supplied to the hot air supply pipe 15 is higher than the pressure acting on the expansion 47 during normal operation of the pulverizer 5 (that is, a situation where no abnormality such as rapid combustion occurs). The pressure is set lower than the pressure at which various devices (for example, the primary ventilator 17 and the air preheater 19) arranged on the upstream side of the air flow are damaged. In the present embodiment, the expansion 47 is supposed to break, but the present invention is not limited to this. Other parts that can be exchanged, such as a part of the flange joint or a measurement seat, are broken (opened). ) May be formed.
The hot air supplied by the hot air supply pipe 15 is guided into the housing 41 as indicated by the arrow A1 and supplied to the lower space S1 located below the crushing table 45.
In FIG. 2, the piping through which the exhaust gas flows from the gas recirculation ventilator 21 is omitted for the sake of illustration.

A space where ignition and rapid combustion may occur will be described. In the present embodiment, the lower space S1, the upper space S2, and the classification space S3 correspond to each other.
A fire extinguishing agent ejection device 60 that injects a fire extinguishing agent into the lower space S1 is provided on a side wall portion of the housing 41 that forms the lower space S1. The fire extinguisher jet device 60 includes a first fire extinguisher jet part 60A and a second fire extinguisher jet part 60B. The first fire extinguishing agent ejection part 60A and the second extinguishing agent ejection part 60B are provided in pairs. That is, the first extinguishing agent ejection part 60A and the second extinguishing agent ejection part 60B are provided close to each other. In addition, you may arrange | position the 1st fire extinguishing agent ejection part 60A and the 2nd fire extinguishing agent ejection part 60B separately.
In the present embodiment illustrated in FIG. 2, for example, two extinguishing agent ejection devices 60 (two each of the first extinguishing agent ejection unit 60 </ b> A and the second extinguishing agent ejection unit 60 </ b> B) are provided in the lower space S <b> 1. And are provided so as to face each other with the central axis of the housing 41 interposed therebetween. However, the number of the extinguishing agent ejection devices 60 is not limited to two, and is determined by the size of the lower space S1.

In the lower space S1, a pressure sensor 61 may be provided at a position indicated by a cross. The pressure sensor 61 includes a first pressure sensor 61A and a second pressure sensor 61B, and the first pressure sensor 61A and the second pressure sensor 61B are provided in pairs. That is, the first pressure sensor 61A and the second pressure sensor 61B are provided close to each other. Note that the first pressure sensor 61A and the second pressure sensor 61B may be spaced apart.
The pressure sensor 61 in the lower space S1 can be omitted (described later).

  A rotary separator (classifier) 53 is provided on the upper portion of the housing 41. The rotary separator 53 is disposed so as to surround the fuel supply pipe 43 and rotates around the fuel supply pipe 43. Along with the rotation of the rotary separator 53, a plurality of blades 53a attached to the outer periphery thereof travel in the circumferential direction. The fine powder of biomass fuel pulverized by the pulverization table 45 and the pulverization roller 46 is wound upward by the flow of hot air (see arrow A2) rising from the lower space S1 through the outer peripheral side of the pulverization table 45. Of the fine powder that has been wound up, the fine powder having a relatively large diameter is knocked down by the blade 53a, returned to the grinding table 45, and ground again. Thereby, the rotary separator 53 classifies the fine powder by the size of the fine powder, and the fine powder of the biomass fuel having a predetermined diameter or less is conveyed from the fine powder fuel supply pipe 7 together with the hot air and carried out.

An upper space S <b> 2 is formed between the upstream side of the rotary separator 53 (the lower side of the rotary separator 53) and the upper side of the crushing table 45. A fire extinguishing agent ejection device 60 that injects a fire extinguishing agent into the upper space S2 is provided on the side wall of the housing 41 that forms the upper space S2. In FIG. 2, for example, two extinguishing agent ejection devices 60 are provided in the upper space S <b> 2, and are provided so as to be opposed to each other across the central axis of the housing 41. The number of fire extinguishing agent ejection devices 60 is not limited to two. However, the number of the extinguishing agent ejection devices 60 is determined by the size of the upper space S2.
For example, when two extinguishing agent jetting devices 60 are provided, the extinguishing agent jetting device 60 in the upper space S2 and the lower space are provided so as to be opposed to each other across the central axis of the housing 41. The fire extinguishing agent ejection device 60 of S1 does not need to be at the same position in the circumferential direction of the housing 41, and may be displaced in the circumferential direction. For this reason, it is possible to inject the fire extinguishing agent with less bias over a wide area of both the upper space S2 and the lower space S1.

  In the upper space S2, a pressure sensor 61 for detecting rapid combustion is provided at a position indicated by a cross. The number of pressure sensors 61 is determined by the volume in the upper space S2, and is, for example, two in the present embodiment shown in FIG. The number of pressure sensors 61 is not limited to two.

  A pulverized fuel supply pipe 7 is connected to the ceiling portion 42. The pulverized fuel supply pipe 7 discharges the fine powder of biomass fuel after being classified by the rotary separator 53 together with hot air as indicated by an arrow A3 and guides it to the boiler body 3 (see FIG. 1). A classification space S3 is formed in a space downstream of the rotary separator 53 and upstream of the pulverized fuel supply pipe 7 (that is, an inner space surrounded by the blades 53a of the rotary separator 53).

  The ceiling portion 42 that forms the classification space S3 is provided with a fire extinguishing agent ejection device 60 that injects a fire extinguishing agent into the classification space S3. In FIG. 2, the number of extinguishing agent ejection devices 60 provided in the classification space S3 is, for example, one. The number of fire extinguishing agent ejection devices 60 is not limited to one. However, the number of the extinguishing agent ejection devices 60 is determined by the size of the classification space S3.

  In the classification space S3, a pressure sensor 61 for detecting rapid combustion is provided at a position indicated by a cross. The number of pressure sensors 61 provided in the classification space S3 is determined by the volume in the classification space S3, and is, for example, one in the present embodiment shown in FIG. The number of pressure sensors 61 is not limited to one.

  As a fire extinguishing agent ejected from the extinguishing agent ejection device 60 provided in the lower space S1, the upper space S2, and the classification space S3 (that is, the extinguishing agent ejected from the first extinguishing agent ejection portion 60A and the second extinguishing agent ejection portion 60B). As long as it has a fire extinguishing function, any type can be used. For example, powder (sodium bicarbonate: generally sodium bicarbonate, etc.) is used.

  The pressure sensor 61 provided in the lower space S1, the upper space S2, and the classification space S3 detects an increase in pressure when the biomass fuel ignites in the pulverizer 5 and rapid combustion occurs. The output of the pressure sensor 61 is transmitted to a control unit (not shown). The control unit determines the occurrence of rapid combustion from the pressure value transmitted from the pressure sensor 61, and controls the operation of the extinguishing agent ejection device 60 provided in the lower space S1, the upper space S2, and the classification space S3 based on the result. To do.

Specifically, as will be described below, the control unit determines the occurrence of rapid combustion and controls the operation of the extinguishing agent ejection device 60.
The control unit always grasps the operating state of the pulverizer 5. The operation state of the pulverizer 5 may be automatically determined by the control unit or may be manually input.
The control unit determines that rapid combustion has occurred when the pressure detected by the first pressure sensor 61A exceeds a predetermined first threshold value when the operation state of the pulverizer 5 is the normal operation state (first operation state). To do. When it is determined that rapid combustion has occurred in the normal operation state, the fire extinguishing agent is controlled to be ejected from the first extinguishing agent ejection unit 60A substantially simultaneously with this.
The control unit also generates rapid combustion when the pressure detected by the second pressure sensor 61B exceeds a predetermined second threshold value when the operation state of the pulverizer 5 is in the stop operation state (second operation state). Judge that When the control unit determines that rapid combustion has occurred in the stop operation state, control is performed so that the extinguishing agent is ejected from the second extinguishing agent ejection unit 60B substantially simultaneously.

  The normal operating state means an operating state in which the biomass fuel is pulverized into fine powder in the pulverizer 5 and the pulverized biomass fuel fine powder is supplied to the boiler body 3 by hot air for conveyance. Further, the stop operation state means an operation state including both a state where the pulverizer 5 is not operating (when operation is stopped) and a state where the grinder 5 is shifting to operation stop (when operation is stopped). In the state where the operation has been stopped, in order to stop the operation, the rotary separator 53 is rotated at a high speed to clean the rotary separator 53, or biomass fuel and hot air are supplied into the housing 41. There is a clearing state where the pulverizing table 45 and the scraper 48 are rotated in a state where the biomass fuel is not discharged and the biomass fuel is discharged from the pulverizer 5.

  The occurrence of rapid combustion by the control unit may be determined as follows. The control unit determines that rapid combustion has occurred when any of the pressure sensors 61 provided in the lower space S1, the upper space S2, and the classification space S3 exceeds a predetermined threshold. Or, in the normal operation state, two first pressure sensors 61A among the pressure sensors 61 provided in the upper space S2 and one first pressure sensor 61A among the pressure sensors 61 provided in the classification space S3 are configured. If two of the three first pressure sensors 61A exceed a predetermined threshold, it may be determined that rapid combustion has occurred and erroneous determination may be suppressed. Similarly, in the stop operation state, the control unit also includes two second pressure sensors 61B among the pressure sensors 61 provided in the upper space S2 and one second pressure among the pressure sensors 61 provided in the classification space S3. When two of the three second pressure sensors 61B configured by the sensor 61B exceed a predetermined threshold, it may be determined that rapid combustion has occurred and erroneous determination may be suppressed. When it is determined by the control unit that rapid combustion has occurred, the fire extinguishing agent is controlled to be ejected from the extinguishing agent ejection device 60 provided in the lower space S1, the upper space S2, and the classification space S3 substantially simultaneously.

  The first threshold is set based on the pressure in the housing 41 in the normal operation state. Specifically, the pressure is set to a pressure obtained by adding a predetermined pressure (for example, 200 Aq or more and 500 Aq or less) to the pressure in the housing 41 in the normal operation state and in a normal operation. The second threshold is set based on the highest pressure in the housing 41 in the stop operation state. Specifically, since the pressure value is different depending on each operation state in the stop operation state, the highest pressure in the housing 41 when operating normally is a predetermined pressure (for example, 200 Aq or more). The pressure is set to 500 Aq or less). Note that the pressure in the housing when operating normally during normal operation and the pressure within the housing 41 when operating normally during stop operation are different pressure values. The first threshold value and the second threshold value are different pressures. Specifically, during the stop operation state, the pressure during normal operation is related to the fact that a large amount of inert gas is supplied into the housing 41 during the clearing state in which biomass fuel is discharged from the pulverizer 5. Higher than. That is, in the stop operation state, an operation of injecting an inert gas is performed for the purpose of reducing the oxygen concentration in the housing 41, and the internal pressure of the housing 41 increases by the amount of input of the medium. The second threshold is set higher than the first threshold.

  The control unit includes, 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 or the like in the form of a program as an example, and the CPU reads the program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is preinstalled 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. Etc. may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

The reason why the fire extinguishing agent ejection device 60 is installed in the lower space S1, the upper space S2, and the classification space S3 will be described.
The reason why the extinguishing agent jetting device 60 is installed in the upper space S2 and the classification space S3 is that there is a large amount of biomass fuel after pulverization in the upper space S2 due to the upper portion of the pulverization table 45, and the classification space S3. Then, when there are many biomass fuels which became fine powder, and when the hot air used as carrier gas is heated, it is easier to ignite compared with other spaces. In addition, sparks are generated due to the presence of volatile matter and foreign matter from biomass fuel, and it is a space that is easy to ignite compared to other spaces, and it is a space that exists as fine powder and has a large surface area that is easy to ignite. is there. Accordingly, the pressure sensor 61 is also installed in such a space so that the fire can be extinguished at an appropriate timing.

  On the other hand, the lower space S1 is below the pulverizing table 45, and the biomass fuel pulverized on the pulverizing table 45 is wound up by the hot air supplied to the lower space S1, so that finer powder than the upper space S2 is generated. Abundance is small. However, there are not a few fine powders of biomass fuel, and there is a risk of ignition compared to other spaces because the space is supplied with a large amount of hot air. Therefore, the fire extinguishing agent ejection device 60 is provided. However, the pressure sensor 61 may be omitted, or a signal from the pressure sensor 61 in the upper space S2 or the classification space S3 close to the lower space S1 may be used.

  As described above, hot air is supplied from the hot air supply pipe 15 to the lower space S1, passes through the upper space S2, passes through the classification space S3, and flows to the pulverized fuel supply pipe 7. The fuel pulverized between the pulverizing roller 46 and the pulverizing table 45 becomes fine powder, wound up by hot air, classified through the rotary separator 53, and then passed through the pulverized fuel supply pipe 7 to the burner 9 of the boiler body 3. Led. For this reason, in addition to the lower space S1, the upper space S2, and the classification space S3, there is a space that is affected by rapid combustion.

Next, a space in which ignition may occur in a different space and the spread of rapid combustion may occur, unlike a space where ignition and rapid combustion occur. In the present embodiment, the fuel supply pipe 43, the hot air supply pipe 15, and the pulverized fuel supply pipe 7 correspond.
The fire extinguishing agent ejection device 60 is also provided in the fuel supply pipe 43, the hot air supply pipe 15, and the pulverized fuel supply pipe 7. The fire extinguishing agent ejection device 60 provided in the hot air supply pipe 15 is provided on the downstream side of the hot air flow with respect to the joining portion 15a. Each extinguishing agent ejection device 60 is controlled by the control unit in the same manner as the above-described extinguishing agent ejection device 60. These fire extinguishing agent jetting devices 60 prevent the spread of rapid combustion.
When an expansion 47 that breaks at a predetermined pressure is provided in a part of the cooling air circulation pipe 15c, the expansion of the expansion 47 does not cause the pressure inside the hot air supply pipe 15 to exceed a predetermined pressure. Thus, when the space has a capacity capable of suppressing the spread of rapid combustion, the extinguishing agent jetting device 60 provided in the hot air supply pipe 15 may be omitted.

  Further, the fuel supply pipe 43, the hot air supply pipe 15 and the pulverized fuel supply pipe 7 need to be provided with a fire extinguishing agent jetting device 60 because there is a risk of fire spread. However, since the possibility of ignition is low, the pressure sensor 61 is provided. It is not necessary to provide the extinguishing agent at an appropriate timing in consideration of the propagation time of rapid combustion by using the signal of the pressure sensor 61 in the upper space S2 and the classification space S3 close to the fire spreading space. It is preferable.

  The installation position of the extinguishing agent ejection device 60 is installed in consideration of the propagation time of rapid combustion. Specifically, when rapid combustion occurs, it is installed at a position where the extinguishing agent can be injected before and after the flame propagation of rapid combustion reaches. By injecting the fire extinguishing agent before and after the spread of fire spread, the pressure rise can be suppressed.

  On the other hand, when the installation position of the extinguishing agent ejection device 60 is closer to the location where the rapid combustion occurs than the appropriate position, the fire extinguishing agent is ejected too early with respect to the spread of the flame, so that the flame due to the spread of fire spread does not develop. The fire extinguisher is injected after passing through the extinguishing agent jet device 60 as it is, and the spread of fire spread cannot be effectively suppressed, and the fire develops and spreads after the extinguishing agent is injected, and the pressure rises. .

  Moreover, when the installation position of the extinguishing agent ejection device 60 is far from the location where the rapid combustion occurs than the appropriate position, the fire extinguishing agent is ejected after the spread of the fire spread, and the fire extinguishing is not in time or the propagation of the fire spread is not performed. It is necessary to put in a fire extinguisher in a state larger than that at the time of design, and a larger amount of fire extinguishing agent is required than the assumed amount of fire extinguishing agent, so that rapid combustion cannot be suppressed efficiently. This increases the cost.

The crusher 5 having the above-described configuration operates as follows.
When the biomass fuel is introduced from the fuel supply pipe 43 toward the center of the pulverizing table 45 (see arrow A0), the biomass fuel is guided to the outer peripheral side of the pulverizing table 45 by the centrifugal force generated by the rotation of the pulverizing table 45, and pulverized. It is sandwiched between the rollers 46 and pulverized. The pulverized biomass fuel is rolled up by the hot air guided from the hot air supply pipe 15 (see arrow A2) and guided to the rotary separator 53. In the rotary separator 53, the fine powder having a relatively large diameter is struck down by the blade 53a and returned to the crushing table 45. The fine powder after classification that has passed through the blade 53a is guided to the fine fuel supply pipe 7 together with hot air and supplied to the burner 9 (see FIG. 1) of the boiler body 3.

  When the biomass fuel ignites and rapid combustion occurs during the normal operation state of the pulverizer 5 as described above, the control unit performs rapid combustion according to the detection value of the first pressure sensor 61A appropriately provided in each space. Generation | occurrence | production is judged and a fire extinguisher is injected at an appropriate timing from each 1st fire extinguishing agent ejection part 60A provided appropriately in each space. In addition, when the biomass fuel is ignited and rapid combustion occurs when the pulverizer 5 is in the stop operation state, the control unit causes the rapid combustion to occur according to the detection value of the second pressure sensor 61B appropriately provided in each space. The fire extinguishing agent is jetted at an appropriate timing from each second extinguishing agent ejection part 60B appropriately provided in each space.

Specifically, the control unit performs the following control.
First, the control unit determines the operating state of the pulverizer 5. When the operation state is the normal operation state, the first pressure sensor 61A detects the pressure in the housing 41 (pressure detection step), and transmits the detected pressure to the control unit. The control unit determines whether or not the pressure detected by the first pressure sensor 61A is equal to or greater than a first threshold value. If it is greater than or equal to the first threshold, it is determined that the biomass fuel has ignited in the pulverizer 5 and rapid combustion has occurred, and the extinguishing agent is ejected from each first extinguishing agent ejection part 60A (first extinguishing agent ejection Step). When the detected pressure is lower than the first threshold, the process returns to the step of determining the operating state. In addition, after the fire extinguishing agent is ejected, the process returns to the step of determining the operation state. Moreover, when cleaning the fire extinguishing agent ejected from each first extinguishing agent ejecting portion 60 </ b> A, the operation proceeds to the operation of stopping the pulverizer 5.
On the other hand, when the operation state is the stop operation state, the second pressure sensor 61B detects the pressure in the housing 41 (pressure detection step) and transmits the detected pressure to the control unit. The control unit determines whether or not the pressure detected by the second pressure sensor 61B is equal to or greater than a second threshold value. If it is equal to or greater than the second threshold, it is determined that the biomass fuel has ignited in the pulverizer 5 and rapid combustion has occurred, and the extinguishing agent is ejected from each second extinguishing agent ejection part 60B (second extinguishing agent ejection Step). If the detected pressure is lower than the second threshold, the process returns to the step of determining the operating state. Moreover, when cleaning the extinguishing agent ejected from each second extinguishing agent ejection part 60 </ b> B, the operation proceeds to the operation of completely stopping the pulverizer 5.

According to this embodiment, there exist the following effects.
In the pulverizer 5, there is a possibility that rapid combustion may occur in any of the normal operation state and the stop operation state.
In this embodiment, different threshold values are set for the normal operation state and the stop operation state. Specifically, the pulverizer 5 sets a first threshold based on the pressure in the housing 41 in the normal operation state, and the pulverizer 5 sets the second threshold based on the pressure in the housing 41 in the stop operation state. ing. Although the pressure value during normal operation differs between the normal operation state and the stop operation state, the threshold value corresponding to each operation state is set as described above, so that in any operation state, in the housing 41. The occurrence of rapid combustion can be determined.
In addition, different extinguishing agent ejection parts are operated in the normal operation state and the stop operation state. Therefore, in any operating state, a fire extinguisher is prepared for each operating state. Therefore, when rapid combustion occurs in the housing 41, the fire extinguisher is ejected to suppress rapid combustion. be able to.

  Therefore, for example, rapid combustion occurs in the pulverizer 5 during normal operation, and the first fire extinguisher jet part 60 </ b> A injects a fire extinguisher and suppresses rapid combustion, so that the pulverizer 5 is stopped. Even when rapid combustion occurs in the pulverizer 5 again during operation in the operating state, the second pressure sensor 61B and the control unit detect rapid combustion, and the second extinguishing agent ejection unit 60B By injecting a fire extinguisher, rapid combustion generated in the pulverizer 5 can be suppressed.

  Moreover, 60 A of 1st extinguishing agent ejection parts and the 2nd extinguishing agent ejection part 60B are provided in pairs. Thereby, when performing installation and maintenance of the first fire extinguishing agent ejection part 60A and the second extinguishing agent ejection part 60B, the installation work of the first extinguishing agent ejection part 60A and the second extinguishing agent ejection part 60B is performed simultaneously. be able to. Therefore, compared with the case where 60 A of 1st extinguishing agent ejection parts and the 2nd extinguishing agent ejection part 60B are provided separately, while reducing the work burden at the time of installation, the work burden at the time of a maintenance can also be reduced. it can.

Moreover, the expansion 47 provided in a part of the hot air supply pipe 15 is broken by a predetermined pressure acting from the inside. As a result, when rapid combustion occurs in the pulverizer 5 and the pressure rise in the housing 41 propagates into the hot air supply pipe 15, the expansion 47 is generated when the pressure in the hot air supply pipe 15 reaches a predetermined pressure. Break through. When the expansion 47 breaks, the pressure escapes from the broken portion, so that an increase in pressure in the hot air supply pipe 15 can be suppressed. Therefore, the pressure in the hot air supply pipe 15 can be maintained below a predetermined pressure. Therefore, the pressure inside the hot air supply pipe 15 becomes higher than expected, and the hot air supply pipe 15 other than the expansion 47 portion can be prevented from being damaged. Further, it is possible to prevent various devices upstream of the flow of hot air supplied by the hot air supply pipe 15 from being damaged by the propagation of pressure. In addition, since the damaged portion of the hot air supply pipe 15 is the expansion 47 that can be easily replaced, the damaged portion can be easily repaired.
Furthermore, by maintaining the pressure in the hot air supply pipe 15 at a predetermined pressure or less, a rapid increase in the pressure in the casing of the pulverizer 5 is also suppressed, and the density at which the fine powder of biomass fuel exists is locally increased. To suppress the rapid combustion when the fire extinguisher in the pulverizer 5 is jetted out more effectively. can do.

  Further, since the expansion 47 already installed in a part of the hot air supply pipe 15 is broken, a device such as a rupture disk for suppressing the pressure rise is provided in the hot air supply pipe 15 separately. The pressure in the hot air supply pipe 15 can be released without any problem. Further, when a separate device or the like is provided for the existing pulverizer 5, it is necessary to secure a new space for disposing the device, so that the layout of the piping may have to be changed. However, if it is the structure of this embodiment, the raise of a pressure can be suppressed, without changing the layout of the conventional piping. Therefore, space saving and cost reduction can be achieved as compared with the case where a separate device or the like is provided.

In the present embodiment, an example in which biomass fuel is pulverized as a solid fuel to be pulverized by the pulverizer 5 is described. However, the solid fuel to be pulverized is not limited to biomass fuel, and may be coal with high ignitability. Moreover, the grinder 5 may be of a form that grinds only coal or may be a form that grinds only biomass fuel. Moreover, the form which grind | pulverizes biomass fuel with coal may be sufficient, and the form which switches and grind | pulverizes coal and biomass fuel may be sufficient.
In the present embodiment, an example in which the first pressure sensor 61A and the second pressure sensor 61B are separately provided and the pressure sensor that detects the pressure depending on the operation state of the pulverizer 5 has been described has been described. The pressure may be detected by one pressure sensor in all operating states.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described.
This embodiment is different from the first embodiment in that the pulverizer 5 is in a form of pulverizing by switching between coal and biomass fuel. Since other configurations are the same as those in the first embodiment, description thereof is omitted.
In the present embodiment, the pressure sensor 61 is stopped when pulverizing coal, which is a solid fuel with low ignitability. On the other hand, when pulverizing biomass fuel, which is a solid fuel with high ignitability, the extinguishing agent ejection device 60 and the pressure sensor 61 are operated by the method described in the first embodiment. In this manner, the extinguishing agent is not injected from the first extinguishing agent ejection unit 60A and the second extinguishing agent ejection unit 60B or is switched depending on the type of solid fuel to be pulverized by the pulverizer 5.
The stop of the pressure sensor 61 and the switching of operation may be performed manually by an operator or automatically by a control unit.

According to this embodiment, there exist the following effects.
Since the control unit determines the rapid combustion based on the pressure increase in the pulverizer 5, when the pressure increase due to other factors occurs despite the fact that the rapid combustion has not occurred, There is a possibility that it is erroneously determined that rapid combustion has occurred even though combustion has not occurred. If an erroneous determination is made in this way, unnecessary fire extinguishing agent injection (malfunction) is performed. In the present embodiment, when pulverizing coal, which is a solid fuel with low ignitability (that is, low possibility of rapid combustion), fire extinguishing is performed from the first extinguishing agent ejection unit 60A and the second extinguishing agent ejection unit 60B. The agent is not sprayed. Therefore, even when the pressure rises due to a factor other than the rapid combustion in a state where the rapid combustion has not occurred, the malfunction of injecting the extinguishing agent into the pulverizer 5 can be prevented.

  In addition, when pulverizing coal which is solid fuel with low ignitability, the first threshold value and the second threshold value are set when the biomass which is fuel with higher ignitability than coal is used as solid fuel. And you may adjust to a value (for example, 2000Aq or more) higher than a 2nd threshold value. And when pulverizing biomass fuel which is solid fuel with high ignitability, the 1st threshold and the 2nd threshold are set up as explained in a 1st embodiment. Thus, the first threshold value and the second threshold value are adjusted according to the type of solid fuel. The first threshold value and the second threshold value may be adjusted manually by the operator or automatically by the control unit.

  In this way, when the coal is pulverized, the extinguishing agent jetting device 60 can be made not to operate easily by setting the pressure that is not actually reached as the threshold value. Therefore, even when the pressure rises due to a factor other than the rapid combustion in a state where the rapid combustion has not occurred, the malfunction of injecting the extinguishing agent into the pulverizer 5 can be prevented.

  Note that the present invention is not limited to the invention according to each of the above embodiments, and can be appropriately modified without departing from the gist thereof. For example, in each of the above embodiments, the fire supply agent jetting device 60 is provided in the fuel supply pipe 43, the hot air supply pipe 15, and the pulverized fuel supply pipe 7, but any one or two of them are extinguished. You may make it provide the agent ejection apparatus 60. FIG.

DESCRIPTION OF SYMBOLS 1 Boiler equipment 3 Boiler main body 5 Crusher 7 Fine fuel supply pipe 9 Burner 11 Biomass silo 13 Bunker 15 Hot air supply pipe (carrier gas supply pipe)
15b Preheated air circulation pipe 15c Cooling air circulation pipe 15d Mixed air circulation pipe 17 Primary ventilator 19 Air preheater 21 Gas recirculation ventilator 23 Electric dust collector 25 Denitration device 27 Induction ventilator 29 Desulfurization device 31 Chimney 40 Bottom surface portion 41 Housing (Casing)
42 ceiling part 43 fuel supply pipe 44 gantry 45 crushing table 46 crushing roller 47 expansion 48 scraper 52 pyrite box 60 extinguishing agent ejection device 60A first extinguishing agent ejection unit 60B second extinguishing agent ejection unit 61 pressure sensor 61A first pressure sensor 61B Second pressure sensor

Claims (7)

A crusher for crushing solid fuel into finely divided solid fuel,
A casing constituting an outer shell of the crusher;
A pressure sensor for detecting the pressure in the housing;
When the pressure detected by the pressure sensor is equal to or higher than a predetermined first threshold when the pulverizer is in the first operating state, a first fire extinguishing agent ejection unit that ejects an extinguishing agent into the housing;
In a second operation state where the pulverizer is in an operation state different from the first operation state, when the pressure detected by the pressure sensor is equal to or greater than a second threshold value which is a threshold value different from the first threshold value, A pulverizer comprising: a second fire extinguishing agent ejection unit that ejects the extinguishing agent into the housing. In the first operation state, the pulverizer is in a normal operation state,
The second operation state is a stop operation state including a time when the pulverizer is stopped and a transition to stop operation,
The first threshold is set based on the pressure in the casing in the normal operation state,
The pulverizer according to claim 1, wherein the second threshold is set based on a maximum pressure in the casing in the stop operation state.   The pulverizer according to claim 2, wherein the second threshold is set higher than the first threshold.   The pulverizer according to any one of claims 1 to 3, wherein the first extinguishing agent ejection part and the second extinguishing agent ejection part are provided as a pair.   The pulverizer according to any one of claims 1 to 4, wherein the extinguishing agent is not injected from the first extinguishing agent ejection part and / or the second extinguishing agent ejection part depending on the type of the solid fuel. . A carrier gas supply pipe through which the carrier gas supplied into the housing flows,
The pulverizer according to any one of claims 1 to 5, wherein a part of the carrier gas supply pipe is opened when the inside of the carrier gas supply pipe has a predetermined pressure or higher. A method of operating a pulverizer that pulverizes solid fuel supplied in a casing constituting an outer shell,
A pressure detecting step for detecting pressure in the housing;
When the pressure detected in the pressure detection step is equal to or higher than a predetermined first threshold value when the pulverizer is in the first operation state, a first fire extinguishing agent that ejects a fire extinguishing agent from the first fire extinguishing agent ejecting portion in the housing Agent ejection step,
In the second operation state where the pulverizer is in an operation state different from the first operation state, when the pressure detected in the pressure detection step is equal to or higher than a second threshold value which is a threshold value different from the first threshold value, A pulverizer operating method comprising: a second fire extinguishing agent jetting step for jetting a fire extinguishing agent from a second fire extinguishing agent jetting part in the casing.

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