JP2020063893A - Ash treatment system, power generation plant, and control method for ash treatment system - Google Patents

Abstract

To restrain unevenness in an amount of ash per unit time transferred to an ash treatment device.SOLUTION: An ash treatment system comprises: an ash treatment device for treating ash; a first system 68 comprising a plurality of cyclone dust collector hoppers 63 for storing the ash caught by a cyclone dust collector, and for transferring the ash discharged from the cyclone dust collector hoppers 63 to the ash treatment device; a second system 69 comprising an electric dust collector hopper 62 for storing the ash caught by an electric dust collector, and for transferring the ash discharged from the electric dust collector hopper 62 to the ash treatment device; and a control device for discharging and transferring the ash stored in the electric dust collector hopper 62 after discharging and transferring the ash stored in the cyclone dust collector hoppers 63.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an ash processing system, a power plant, and a method for controlling the ash processing system.

  In a thermal power plant or the like that burns a carbon-containing solid fuel (for example, coal) that is a fuel to generate power, ash (for example, fly ash (coal ash)) is generated when the carbon-containing solid fuel is burned. The generated ash is captured by various devices such as a cyclone dust collector and an electric dust collector, and is temporarily stored in a hopper provided in each device. The ash temporarily stored in each hopper is then transported to the ash processing device. The ash processing device collects the ash that has been conveyed by a filter. The collected ash is stored in the tank and then periodically discharged from the tank to the transport vehicle.

  Patent Document 1 discloses an apparatus including a plurality of economizer economizer hoppers, denitration apparatus hoppers, air preheater hoppers, and dust collecting apparatus hoppers. The fly ash accumulated in each hopper passes through the ash transport pipe by the air flow generated by the vacuum blower, is centrifugally separated by a cyclone, the ash is collected by the bag filter, and is stored in the fly ash silo. The transportation of fly ash is continued until there is no fly ash in each hopper, and all the hoppers are emptied in sequence.

Japanese Patent Publication No. 3-33966

  However, the apparatus of Patent Document 1 does not consider the order of the hoppers for transporting ash. In the device of Patent Document 1, when ash is continuously transported from a plurality of hoppers of the same system (for example, a plurality of economizer hoppers), the ash is transported to a cyclone, a bag filter and a fly ash silo. The amount of ash per unit time may vary. That is, since the hoppers provided in the same system are arranged in the vicinity of each other and all store ash generated in the same device, the amount of ash to be stored is likely to be about the same. Therefore, if a large amount of ash is generated in the device, a large amount of ash may be accumulated in all the hoppers of the same system. In such a case, if ash is continuously transported from the hopper of the same system, a large amount of ash will be transported to the cyclone, bag filter and fly ash silo within a short time, and the cyclone etc. will operate normally. It might not work. Alternatively, when high temperature ash is transported to the bag filter, the bag filter may be thermally damaged.

  The present invention has been made in view of the above circumstances, and includes an ash processing system, a power generation plant, and an ash processing system that can suppress the uneven distribution of the amount of ash transported to the ash processing device per hour. The purpose is to provide a control method.

In order to solve the above problems, the ash processing system, the power generation plant, and the method for controlling the ash processing system of the present invention employ the following means.
An ash processing system according to one aspect of the present invention includes an ash processing device that processes ash, a first device and a second device, and a plurality of devices that capture the ash, and an ash that is captured by the first device. A first system that has a plurality of first system hoppers for storing and that conveys the ash discharged from the first system hopper to the ash processing device; and at least one first system that stores the ash captured by the second device. A plurality of systems including a two-system hopper and a second system that conveys the ash discharged from the second-system hopper to the ash processing apparatus, and at least one of the first-system hoppers are stored. After discharging and transporting the ash stored in the first system hopper in a state in which the ash is not discharged and transported, the target to be discharged and transported of the next stored ash is And a control unit for selecting the second system hopper. To have.

In the above configuration, the ash stored in the first system hopper is discharged and transported, and then the ash stored in the second system hopper is discharged and transported. In addition, after discharging and transporting the ash stored in the first system hopper in a state where at least one first system hopper is not discharging and transporting the stored ash, the next stored ash is stored. The target for discharging and transporting the existing ash is selected as the second system hopper. As a result, in the first system in which the plurality of first system hoppers are provided, the ash is continuously discharged and conveyed between all the provided first system hoppers, and the processing in the first device is performed. After the end, the second system ash of the second device may not be discharged and transported. Generally, the amount of ash stored in each system hopper is different for each system. Therefore, by not discharging and transporting ash from a specific system hopper continuously, but by interposing the discharge and transport of ash from another system hopper in between, the ash transported to the ash processing device per unit time can be reduced. Can be suppressed.
That is, for example, a large amount of ash may be stored in each of the first system hoppers due to, for example, a large amount of ash being captured in the first device. Even in such a case, the discharge and transfer of ash from the system hoppers of other systems (second system) should be sandwiched without continuously discharging and transferring ash from all the first system hoppers. Therefore, it becomes difficult for a large amount of ash to be transported to the ash processing device within a short time. Therefore, it is possible to suppress uneven distribution of the amount of ash transported to the ash processing apparatus per unit time.

  Further, in the ash processing system according to one aspect of the present invention, the value of the product of the temperature and the amount of ash stored in the first system hopper is the temperature and the amount of ash stored in the second system hopper. It may be larger than the value of the product of.

When the ash transferred to the ash processing device has a high temperature, the temperature of the ash processing device increases due to the transferred ash. Here, it was found that the degree of increase in the temperature of the ash processing device is influenced not only by the temperature of the ash to be conveyed but also by the amount, and the product value of the temperature and the amount of ash (hereinafter referred to as the temperature and amount of ash). The value of the product of and is referred to as the "calorific value of ash").
In the above configuration, ash discharge from one first system hopper and ash discharge from one plurality of first system hoppers of the first device having a large calorific value of ash are not continuously carried out over all of them. After the transportation, the ash is carried out and transported from the second system hopper of the second device in which the amount of heat of ash is smaller than that of the first system. As a result, the ash processing device heated by the ash from the first system hopper can be cooled by the ash from the second system hopper. Therefore, an increase in the temperature of the ash processing apparatus can be suppressed, and thus damage to the ash processing apparatus due to the increase in the temperature can be suppressed. Further, since the temperature rise of the ash processing device can be suppressed, it is not necessary to configure the ash processing device with excellent heat resistance. Therefore, the ash processing device can be constructed at low cost.

  In addition, in the ash treatment system according to one aspect of the present invention, the plurality of systems has a system other than the first system and the second system, and the first system hopper has a temperature of stored ash. The value of the product of and the amount may be the largest among the hoppers included in the plurality of systems.

  In the above configuration, the system has a system other than the first system and the system other than the first system, and the heat amount of the ash stored in the first system hopper is the highest heat amount among the plurality of systems. As a result, it is possible to further suppress the temperature increase of the ash processing apparatus, and thus it is possible to further suppress the damage of the ash processing apparatus due to the temperature increase.

  In addition, in the ash processing system according to one aspect of the present invention, the plurality of systems has a system other than the first system and the second system, and the second system hopper has a temperature of stored ash. The value of the product of and the quantity is the smallest among the hoppers included in the plurality of systems.

  In the above configuration, after the ash is discharged and transported from the first system hopper, the ash is carried out and transported from the second system hopper having the smallest amount of heat of ash among the ash captured by the plurality of devices. With this, the ash from the second system hopper can be more appropriately cooled by the ash processing apparatus, so that the temperature rise of the ash processing apparatus can be further suppressed.

  Further, the ash processing system according to an aspect of the present invention may supply cooling air to the ash processing device after discharging and transporting the ash stored in the second system hopper.

In the above configuration, the cooling air is supplied to the ash processing device after discharging and transporting the ash of the second system hopper, which has a small amount of heat. With this, the ash processing apparatus can be cooled by the cooling air, so that the temperature increase of the ash processing apparatus can be further suppressed.
Since the ash having a small heat amount effectively absorbs the heat of the ash processing device, the cooling effect by the ash stored in the second system hopper having the small heat amount is higher than that by the cooling air. Therefore, after transporting the ash stored in the first system hopper, which has a large amount of heat, and immediately after cooling the ash stored in the first system hopper, the amount of heat that is stored in the first system hopper having a large amount of heat is small. The ash processing device can be cooled more quickly when the ash stored in the second system hopper is transported.

  A power plant according to one aspect of the present invention includes the ash treatment system according to any one of the above, and a combustion device that generates a combustion gas by burning a carbon-containing solid fuel, the ash treatment system, Ash contained in the combustion gas is processed.

  A method for controlling an ash processing system according to an aspect of the present invention is directed to discharging ash stored in one of the first system hoppers among a plurality of first system hoppers storing the ash captured by the first device, and The first step of carrying, and after the first step, storing the ash captured by the second device while not discharging and carrying the ash stored in at least one of the first system hoppers And a second step of discharging and transporting the ash stored in the second system hopper.

  According to the present invention, it is possible to suppress the uneven distribution of the amount of ash transported to the ash processing apparatus per unit time.

It is a schematic block diagram which shows the power generation plant to which the ash processing system which concerns on embodiment of this invention is applied. It is a schematic block diagram which shows the ash processing system applied to the power generation plant of FIG. In the ash processing system of FIG. 2, it is a chart which shows the temperature of ash stored in the hopper provided in each system, the amount, and the amount of heat. It is a figure which shows the order which conveys ash in the ash processing system of FIG. It is a graph which shows the temperature of the vacuum bag filter in the ash processing system of FIG. 2, and the relationship of time. It is a figure which shows the order which ash is conveyed in the ash processing system which concerns on a comparative example. It is a graph which shows the temperature of the vacuum bag filter in the ash processing system which concerns on a comparative example, and the relationship of time.

An embodiment of an ash processing system, a power generation plant, and a method for controlling the ash processing system according to the present invention will be described below with reference to the drawings.
The ash processing system 59 according to the present embodiment is applied to, for example, the thermal power plant (power plant) 1 shown in FIG.
In addition, in the present embodiment, the upper side and the upper side indicate the direction and the portion on the vertically upper side. Similarly, “down” indicates the direction and the portion on the vertically lower side.

  As shown in FIG. 1, the thermal power plant 1 can use, for example, pulverized coal obtained by pulverizing coal (carbon-containing solid fuel) as a solid fuel, burn the pulverized coal, and recover heat generated by the combustion. A possible pulverized coal burning boiler 10 is provided.

  The pulverized coal burning boiler 10 has a furnace 11 and a combustion device 12. The furnace 11 has, for example, a hollow rectangular shape and is installed along the vertical direction. A combustion device 12 is provided below a furnace wall constituting the furnace 11.

  The combustion device 12 has a plurality of combustion burners 21, 22, 23, 24, 25 installed on the furnace wall. In this embodiment, for example, the combustion burners 21, 22, 23, 24, and 25 are arranged at equal intervals in the circumferential direction as one set, and five sets are set in the vertical direction. They are arranged in 5 stages.

  The combustion burners 21, 22, 23, 24, 25 are connected to the pulverized coal machines (mills) 31, 32, 33, 34, 35 via the pulverized coal supply pipes 26, 27, 28, 29, 30. ing. In the pulverized coal machines 31, 32, 33, 34, 35, a rotary table (not shown) is rotatably supported in a housing with a rotary shaft center along the vertical direction, and above the rotary table (not shown). A plurality of crushing rollers (not shown) are rotatably supported in conjunction with the rotation of the rotary table. Therefore, when coal is introduced between the plurality of crushing rollers and the rotary table, the pulverized coal is pulverized to a predetermined size and the pulverized coal is classified by the conveying air (primary air) into the pulverized coal supply pipe 26, The combustion burners 21, 22, 23, 24, 25 can be supplied from 27, 28, 29, 30.

  Further, in the furnace 11, a wind box 36 is provided at the installation position of each combustion burner 21, 22, 23, 24, 25, and one end portion of an air duct 37 is connected to the wind box 36. A blower 38 is connected to the other end of the duct 37. Therefore, the combustion air (secondary air, tertiary air) sent by the blower 38 is supplied from the air duct 37 to the wind box 36, and the combustion burners 21, 22, 23, 24, 25 are supplied from the wind box 36. Can be supplied to.

  Therefore, in the combustion device 12, each combustion burner 21, 22, 23, 24, 25 can blow a pulverized fuel mixture (fuel gas) obtained by mixing pulverized coal and primary air into the furnace 11. Secondary air can be blown into the furnace 11, and a flame can be formed by igniting a pulverized fuel mixture with an ignition torch (not shown).

  A flue 40 is connected to an upper portion of the furnace 11, and the flue 40 is provided with superheaters (super heaters) 41 and 42 for recovering heat of combustion gas as a heat transfer section (heat recovery section). Heaters 43, 44 and economizers 45, 46, 47 are provided, and heat exchange is performed between the combustion gas generated by combustion in the furnace 11 and water, and the combustion gas is used as exhaust gas. It is introduced downstream of the flue 40.

  The flue 40 is connected to an exhaust gas pipe 48 at the downstream side thereof, through which exhaust gas having undergone heat exchange is discharged. The exhaust gas pipe 48 is provided with an air preheater 49. In the air preheater 49, heat is exchanged between the air flowing through the air duct 37 and the exhaust gas flowing through the exhaust gas pipe 48 to raise the temperature of the combustion air supplied to the combustion burners 21, 22, 23, 24, 25. be able to.

  In the exhaust gas pipe 48, a cyclone dust collector (first device) 61 and a denitration device 50 are provided in order from the upstream side, on the downstream side of the economizer 47 and on the upstream side of the air preheater 49. There is. The cyclone dust collector 61 separates and removes foreign matter contained in the exhaust gas by centrifugal separation. The denitration device 50 denitrates the exhaust gas by removing harmful substances such as NOx from the exhaust gas. The exhaust gas pipe 48 is provided with an electrostatic precipitator (second device) 51, an induced air blower 52, and a desulfurization device 53 in order from the upstream side on the downstream side of the air preheater 49. The electric dust collector 51 separates and removes foreign substances contained in the exhaust gas by an electric mechanism. The desulfurization device 53 desulfurizes the exhaust gas by removing sulfur oxides from the exhaust gas. A chimney 54 is provided at the downstream end of the exhaust gas pipe 48.

The pulverized coal burning boiler 10 as described above generates and discharges combustion gas as follows.
When the pulverized coal machines 31, 32, 33, 34, 35 are driven, the produced pulverized coal passes through the pulverized coal supply pipes 26, 27, 28, 29, 30 together with the carrier air, and the combustion burners 21, 22, 23, 24, 25. Further, the heated combustion air is supplied from the air duct 37 to the respective combustion burners 21, 22, 23, 24, 25 via the wind box 36. Then, the combustion burners 21, 22, 23, 24, 25 blow the pulverized fuel mixture, in which the pulverized coal and the carrier air are mixed, into the furnace 11 and the combustion air into the furnace 11, and ignite at this time. A flame can be formed with. In this furnace 11, the pulverized fuel mixture and the combustion air are combusted to generate a flame. When a flame is generated in the lower part of the furnace 11, the combustion gas (exhaust gas) rises in the furnace 11 and the flue It is discharged to 40.

  In the furnace 11, the air supply amount is set to be less than the theoretical air amount with respect to the pulverized coal supply amount, so that the inside is maintained in the reducing atmosphere. Then, the NOx generated by the combustion of the pulverized coal is reduced in the furnace 11, and then the additional combustion of the additional air is completed to complete the oxidative combustion of the pulverized coal and reduce the amount of NOx generated by the combustion of the pulverized coal. .

  At this time, the water supplied by the water supply pump (not shown) is preheated by the economizers 45, 46, 47, and then supplied to the steam drum (not shown) and supplied to each water pipe (not shown) of the furnace wall. Is heated to become saturated steam, and is sent to the steam drum again. Further, the saturated steam in the steam drum is introduced into the superheaters 41 and 42 and superheated by the combustion gas. The superheated steam generated by the superheaters 41 and 42 is supplied to a power generator (not shown) (for example, a steam turbine). Further, the steam taken out in the middle of the expansion process in the steam turbine is introduced into the reheaters 43 and 44, is overheated again, and is returned to the steam turbine. Although the furnace 11 has been described as a drum type (steam drum), the structure is not limited to this.

  After that, in the exhaust gas that has passed through the economizers 45, 46, 47 of the flue 40, harmful substances such as NOx are removed by the denitration device 50, and particulate substances are removed by the cyclone dust collector 61 and the electric dust collector 51, and the desulfurization device. After the sulfur oxides are removed by 53, they are discharged from the chimney 54 into the atmosphere.

Next, the ash treatment system 59 provided in the thermal power plant 1 will be described in detail with reference to FIGS. 1 to 4. As shown in FIG. 2, the ash treatment system 59 includes an ash discharge system 60 and an ash treatment device 75. The ash processing system 59 according to the present embodiment mainly processes particulate ash called fly ash, for example.
As shown in FIGS. 1 and 2, the cyclone dust collector 61, the electric dust collector 51, the economizers 45, 46, 47, the denitration device 50, and the air preheater 49 are located at corresponding positions, respectively. A system hopper 63, an electric dust collector hopper (second system hopper) 62, a economizer hopper 55, a denitration device inlet hopper 64, and an air preheater hopper 65 are provided. The cyclone dust collector hopper 63, the electric dust collector hopper 62, the economizer hopper 55, and the air preheater hopper 65 are arranged vertically below the corresponding devices, and temporarily store the ash captured by the devices. The denitration device inlet hopper 64 is provided on the upstream side of the denitration device 50, and temporarily stores the ash captured by the denitration device inlet duct. Further, as shown by a broken line in FIG. 1, an electrostatic precipitator inlet hopper 58 for temporarily storing the ash captured by the electrostatic precipitator upstream duct may be provided on the upstream side of the electrostatic precipitator 51.
For the sake of illustration, FIG. 1 shows one hopper corresponding to each device and FIG. 2 shows two hoppers, but in the present embodiment, as shown in FIG. Four corresponding hoppers are provided. The number of hoppers described in this embodiment is an example, and the number of hoppers does not have to be four.

As shown in FIG. 2, the ash stored in each hopper is transported to the ash processing device 75 described later via the transport pipe 66. The carrier gas sucked by the vacuum suction blower 67 flows in the carrier pipe 66.
The transfer pipe 66 includes a first transfer pipe 68a connected to the cyclone dust collector hopper 63, a second transfer pipe 69a connected to the electric dust collector hopper 62, a third transfer pipe 70a connected to the economizer hopper 55, and a denitration device. It has a fourth transfer pipe 71a connected to the inlet hopper 64 and a fifth transfer pipe 72a connected to the air preheater hopper 65.

  The ash discharge system 60 conveys the ash stored in the cyclone dust collector hopper 63 to the ash treatment device 75, and the second system 68 conveys the ash stored in the electric dust collector hopper 62 to the ash treatment device 75. System 69, third system 70 that conveys the ash stored in the economizer hopper 55 to the ash treatment device 75, and fourth system 70 that conveys the ash stored in the denitration device inlet hopper 64 to the ash treatment device 75. A system 71 and a fifth system 72 that conveys the ash stored in the air preheater hopper 65 to the ash processing device 75 are provided.

  The first system 68 includes the above-described first transfer pipe 68a, a first ash intake valve 68b provided at a connecting portion between the cyclone dust collector hopper 63 and the first transfer pipe 68a, and a first transfer pipe 68a provided at the first transfer pipe 68a. It has a system switching valve 68c and a first air preheater 68e provided in the first transfer pipe 68a. The first transfer pipe 68a is connected to the lower ends of the four cyclone dust collector hoppers 63. The four cyclone dust collector hoppers 63 are connected side by side at predetermined intervals along the extending direction of the first transfer pipe 68a. Further, a first suction port 68d is provided at the upstream end of the first transfer pipe 68a. The carrier gas (for example, air) sucked from the first suction port 68d flows in the first carrier pipe 68a. The first ash intake valve 68b is an on-off valve, and switches the communication state and the cutoff state between the cyclone dust collector hopper 63 and the first transfer pipe 68a. The first system switching valve 68c is an open / close valve. Further, the first system switching valve 68c is provided on the downstream side of the connection portion with the cyclone dust collector hopper 63, which is provided on the most downstream side, in the first transfer pipe 68a. The first air preheater 68e is provided on the upstream side of the connection portion with the cyclone dust collector hopper 63 arranged on the most upstream side in the first transfer pipe 68a. A heat exchanger having a heat transfer tube is provided inside the first air preheater 68e. The first air preheater 68e heats and dries the carrier gas by exchanging heat between the fluid (for example, steam) flowing in the heat transfer tube and the carrier gas flowing in the first carrier pipe 68a. . The first ash intake valve 68b and the first system switching valve 68c are each controlled by the control device 100 described later.

  The second system 69, the third system 70, the fourth system 71, and the fifth system 72 are, similarly to the first system 68, transfer pipes 69a, 70a, 71a, 72a, ash intake valves 69b, 70b, 71b, respectively. 72b, system switching valves 69c, 70c, 71c, 72c, suction ports 69d, 70d, 71d, 72d and air preheaters 69e, 70e, 71e, 72e. The configurations of the second system 69, the third system 70, the fourth system 71, and the fifth system 72 are the same as those of the first system 68, so detailed description thereof will be omitted.

  The ash treatment device 75 is discharged from the vacuum bag filter 76 connected to the downstream end of the transfer pipe 66, the backwash air injection device 77 that injects backwash air into the vacuum bag filter 76, and the vacuum bag filter 76. And a fly ash tank 78 for storing ash.

  The vacuum bag filter 76 includes a casing 79 that forms an outer shell, and a collecting unit 80 that is disposed inside the casing 79 and that collects ash contained in the carrier gas.

  The housing 79 integrally has a cylindrical portion 82 located at the upper portion and a reduced diameter portion 83 whose upper end is connected to the lower end of the cylindrical portion 82. The diameter-reduced portion 83 has a diameter that decreases downward in the vertical direction, and an opening is formed at the lower end. A transport pipe 66 is connected to a vertically lower portion of the cylindrical portion 82. A carrier gas discharge pipe 84 for discharging carrier gas from the inside of the housing 79 is connected to the vertical upper portion of the cylindrical portion 82. That is, the carrier gas discharge pipe 84 is connected vertically above the connecting portion of the carrier pipe 66.

The collecting unit 80 has a plurality of filter cloths 85 and is arranged inside the cylindrical portion 82. Specifically, the collection unit 80 is arranged vertically above the connecting portion of the carrier pipe 66 and vertically below the connecting portion of the carrier gas discharge pipe 84. In addition, the collection unit 80 is provided inside the cylindrical portion 82 over substantially the entire area in the horizontal direction. Each filter cloth 85 is formed in a tubular shape extending in the vertical direction. The plurality of filter cloths 85 are arranged side by side in the horizontal direction. The collecting unit 80 collects the ash by attaching the ash to the surface of the filter cloth 85.
Here, “collecting ash in the collection unit 80” refers to a situation in which a carrier gas containing ash passes through the collection unit and at least part of the ash is attached to the collection unit 80.

The backwashing air injection device 77 includes a supply device 89 for supplying the backwashing air, a plurality of nozzles (not shown) provided in the housing 79 for injecting the backwashing air toward the filter cloth, and a supply device. It has a backwash air pipe 91 connecting the device 89 and the nozzle, and a backwash air valve 92 provided in the backwash air pipe 91.
The backwash air valve 92 is an opening / closing valve, and the injection time and the injection interval are controlled by opening / closing the backwash air valve 92. The backwash air valve 92 is controlled by the control device 100.

  The fly ash tank 78 stores the ash discharged from the vacuum bag filter 76 inside. For example, the surface of the filter cloth 85 contains ash that has fallen off when collecting ash, and ash that has fallen off due to the injection of backwash air. An ash discharge pipe 93 is connected to the lower end of the fly ash tank 78, and ash is discharged to the outside by the discharge pipe. An ash discharge pipe valve 94 is provided in the ash discharge pipe 93.

  The control device (control unit) 100 controls switching of open / close states of the ash intake valves and the system switching valves. The control device 100 also controls the start and stop of the vacuum suction blower 67 and the open / close state of the backwash air valve 92.

  The control device 100 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 processing 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 the RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is installed in a ROM or other storage medium in advance, provided in a state of being stored in a computer-readable storage medium, or delivered 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 control device 100 switches the open / closed state of each ash intake valve and each system switching valve to process the ash of each hopper in a predetermined order (the ash is discharged from the hopper to the transfer pipe to the ash processing device). The process of carrying) is performed. The discharge and transportation of ash from a plurality of hoppers are performed one by one. That is, the control device 100 selects a hopper for processing ash.
The order of the hoppers for processing the ash is determined based on the amount of heat of the ash stored in the hoppers provided in each system. The amount of heat in this embodiment is the product of the temperature and the amount of ash stored in the hoppers provided in each system.
In the present embodiment, the ash treatment of all the hoppers of the system having a large amount of heat is not continuously performed. That is, in a plurality of hoppers of a system with a large amount of heat, ash is continuously discharged and conveyed between all the provided hoppers to finish the process in the system with a large amount of heat, and then another system The ash will not be discharged or transported. Specifically, in this embodiment, after the ash of the hopper of the system having a large heat quantity is processed, the ash of the hopper of the system having a small heat quantity is processed. Then, after the ash of the hopper of the system having a small heat amount is processed, the ash of the other hopper of the system having a large heat amount is processed.

An example of the temperature, the amount, and the amount of heat of the ash stored in the hopper provided in each system is shown in FIG. Note that CP in FIG. 3 indicates the cyclone dust collector 61, and EP indicates the electric dust collector 51.
As shown in FIG. 3, the ash stored in the cyclone dust collector hopper 63 has a high temperature of 350 ° C. to 400 ° C. and a large amount. Therefore, the calorific value of ash is the largest among the hoppers provided in all systems. On the other hand, the ash stored in the electrostatic precipitator hopper 62 has a low temperature of, for example, 130 ° C to 200 ° C. Therefore, although the amount of ash is large, the amount of heat of ash is small. The ash stored in the economizer hopper 55, the denitration device inlet hopper 64, and the air preheater hopper 65 is as hot as the ash stored in the cyclone dust collector hopper 63 (for example, 350 ° C. to 420 ° C.). Since the amount is small, the amount of heat of ash is smaller than that of ash stored in the cyclone dust collector hopper 63.

  In the present embodiment, when the ash stored in the cyclone dust collector hopper 63 provided in the first system 68 having the largest heat quantity is processed, the hoppers provided in the first system 68 are not continuously processed. There is. Specifically, one ash process in the cyclone dust collector hopper 63 is performed, and then the ash stored in the electric dust collector hopper 62 provided in the second system 69 having the smallest heat amount in another system is processed.

  Next, a method of processing ash from each hopper in the ash processing system 59 according to this embodiment will be described. The outline of the ash processing will be described first, and the order of the hoppers that perform the ash processing will be described later.

  As shown in FIG. 2, the ash captured by the cyclone dust collector 61 is temporarily stored in the cyclone dust collector hopper 63. At this time, the ash intake valves of all the systems and all the system switching valves are closed. Next, only the first system switching valve 68c is opened, the vacuum suction blower 67 is activated, and the warming operation is performed. The warming operation is an operation of removing foreign matter remaining in the pipe and the equipment from the transfer pipe 66 to the inlet of the fly ash tank 78 before performing a normal operation (an operation of transporting and processing ash from each hopper). .

When the warming operation ends, in the present embodiment, as shown in FIG. 4, first, one of the plurality of cyclone dust collector hoppers 63 is selected, and the ash stored in the selected cyclone dust collector hopper 63 is treated. I do.
The ash treatment is performed as follows. The first ash intake valve 68b corresponding to the cyclone dust collector hopper 63 to be processed is opened. By opening the first ash intake valve 68b, the ash in the cyclone dust collector hopper 63 is discharged into the first transfer pipe 68a. The ash discharged into the first transfer pipe 68a is sucked by the vacuum suction blower 67, and is transferred to the ash processing device 75 together with the transfer gas. After the first ash intake valve 68b is opened, the first ash intake valve 68b is closed after a predetermined time has elapsed. In this way, the ash in the cyclone dust collector hopper 63 is gradually discharged while repeatedly opening and closing the first ash intake valve 68b, and when the ash in the hopper becomes empty, the first ash intake valve 68b is closed. When the first ash intake valve 68b is closed, the processing of this hopper is completed and the ash processing of the other hoppers is started. Similarly, when all the hoppers have been treated for ash, the cleanup operation is performed. The clean-up operation is an operation in which the vacuum blower is started after the normal operation is performed to remove foreign matters remaining in the transfer pipe 66.

  The ash transported from each system to the ash processing device 75 via the transport pipe 66 is introduced into the vacuum bag filter 76. The ash introduced into the housing 79 of the vacuum bag filter 76 flows together with the carrier gas toward the carrier gas discharge pipe 84 arranged vertically above. At this time, the carrier gas containing ash passes through the collection unit 80. When passing through the collection unit 80, ash contained in the carrier gas adheres to the surface of the filter cloth 85. In this way, the ash is collected by the collection unit 80. The carrier gas that has passed through the collection unit 80 passes through the vacuum suction blower 67 through the carrier gas discharge pipe 84, and is discharged to the atmosphere. Here, the state in which the ash is collected in the collection unit 80 means a state in which a carrier gas containing ash passes through the collection unit and at least a part of the ash is attached to the collection unit 80. Show.

  In the vacuum bag filter 76, the backwash air is intermittently jetted toward the filter cloth 85 from a nozzle provided vertically above the filter cloth 85. That is, the filter cloth 85 is backwashed. By injecting the backwash air, the filter cloth 85 is deformed, and the ash attached to the surface of the filter cloth 85 is removed from the filter cloth 85. The ash blown off from the filter cloth 85 passes through the opening formed in the vertically lower portion of the housing 79, and is discharged from the vacuum bag filter 76. The ash discharged from the vacuum bag filter 76 includes, for example, ash that has fallen off when the ash is collected on the surface of the filter cloth 85 and ash that has fallen off due to the injection of backwash air. It is stored in a fly ash tank 78 provided vertically below. An ash discharge pipe 93 is connected to the lower end of the fly ash tank 78, and the ash stored in the fly ash tank 78 is periodically discharged to the transport vehicle 110.

  Next, the order of hoppers for processing ash will be described with reference to FIG. CP in FIG. 4 indicates a cyclone dust collector, and EP indicates an electric dust collector. AH indicates an air preheater, and ECO indicates a economizer. Further, (A) to (D) are given to the four hoppers provided in the same system, but the symbols (A) to (D) are the symbols for discriminating each hopper. The position of each hopper is not specified. For example, the hopper marked with (A) may be arranged on the most upstream side in the transfer pipe, or may be arranged on any of the second to fourth positions counted from the upstream side. Further, in FIG. 4, the numbers in parentheses indicate the order of the hoppers that perform the ash treatment.

FIG. 4 shows an example of the order of hoppers that perform ash processing. First, the ash of the cyclone dust collector hopper (A), which is one of the four cyclone dust collector hoppers 63 provided in the first system 68, is treated (first step). Next, the ash of the electrostatic precipitator hopper (A), which is one of the four electrostatic precipitator hoppers 62 provided in the second system 69 different from the first system 68, is processed (second step). Next, the ash of the cyclone dust collector hopper (B) provided in the first system 68 is processed, and then the ash of the electric dust collector hopper (B) provided in the second system 69 is processed. After the ash treatment of the electrostatic precipitator hopper (B) is performed, for example, in the present embodiment, once the ash treatment of the first system 68 and the second system 69 is left, four airs provided in the fifth system 72 are removed. The preheater hoppers (A) to (D) are sequentially processed one by one. When the ash processing of the fifth system 72 is finished, the ash processing of the first system 68 is returned to and the ash processing of the cyclone dust collector hopper (C) is performed. Next, the ash of the electrostatic precipitator hopper (C) provided in the second system 69 is processed, and thereafter, the ash of the cyclone dust collector hopper (D) and the ash of the electric precipitator hopper (D) are sequentially processed. Next, the four economizer hoppers (A) to (D) provided in the third system 70 are sequentially processed one by one. When the ash treatment of the third system 70 is finished, the four denitration device inlet hoppers (A) to (D) provided in the fourth system 71 are sequentially processed one by one.
The ash processing system 59 according to the present embodiment processes the ash of all the hoppers in such an order, for example.

According to this embodiment, the following operational effects are exhibited.
In the present embodiment, the ash stored in one cyclone dust collector hopper 63 provided in the first system 68 is discharged and conveyed (hereinafter, ash carry-out and conveyance is also referred to as “ash treatment”). Next, the ash stored in the electrostatic precipitator hopper 62 provided in the second system 69 is treated. That is, all the cyclone dust collector hoppers 63 provided in the first system 68 are not continuously processed. In general, the amount of ash stored in the hoppers provided in each system is different for each system. Therefore, by not sequentially performing the ash processing of all the hoppers of a specific system, and interposing the ash processing of the hoppers of the other system in between, the ash transferred to the vacuum bag filter 76 per hour can be reduced. It is possible to suppress the deviation of the amount.
For example, in the cyclone dust collector 61, a large amount of ash may be stored in each cyclone dust collector hopper 63 due to, for example, a large amount of ash being captured. Even in such a case, the processes of all the cyclone dust collector hoppers 63 are not continuously performed, and the processes of the hoppers of other systems (in the present embodiment, the second system 69) are interposed therebetween, It becomes difficult for a large amount of ash to be transported to the vacuum bag filter 76 in a short time. Therefore, it is possible to suppress uneven distribution of the amount of ash transported to the vacuum bag filter 76 per unit time.
In particular, the total amount of ash generated in the pulverized coal-fired boiler 10 varies depending on the coal properties and the like, but the distribution ratio of ash to each system does not change significantly, is substantially constant, and the ratio of stored ash is There are many strains and few strains. Therefore, by performing the processing of the hoppers of other systems during the processing of the hoppers of the same system, it is possible to suitably suppress the uneven distribution of the amount of ash conveyed to the vacuum bag filter 76.

  The ash stored in each cyclone dust collector hopper 63 has a high temperature, so the temperature of the vacuum bag filter 76 is raised by the ash being transported. If the temperature of the vacuum bag filter 76 rises excessively, the filter cloth provided on the vacuum bag filter 76 may be burned out.

The degree of increase in the temperature of the vacuum bag filter 76 does not depend only on the temperature of the ash, but is the value of the product of the temperature and the amount of ash to be conveyed (hereinafter, the value of the product of the temperature and the amount of ash is referred to as “ The amount of heat of ash ").
In the present embodiment, all the cyclone dust collector hoppers 63 provided in the first system 68 do not continuously perform the ash treatment of the cyclone dust collector hoppers 63 having the highest calorific value of ash, and one cyclone dust collector hopper 63 is used. Next, after the ash is discharged and conveyed, a hopper different from that of the first system 68 is selected, and in the present embodiment, the ash of the electrostatic precipitator hopper 62 having a small heat amount of ash is processed. As a result, the vacuum bag filter 76 heated by the ash from the cyclone dust collector hopper 63 can be suitably cooled by the ash from the electric dust collector hopper 62. Therefore, the temperature rise of the vacuum bag filter 76 can be suppressed, so that the burning of the filter cloth 85 and the like due to the temperature rise can be suppressed.

Suppression of the temperature rise of the vacuum bag filter 76 in the ash processing system 59 according to this embodiment will be described in detail with reference to FIGS. 5 to 7.
FIG. 5 is a graph showing the relationship between the temperature of the vacuum bag filter 76 and time. Reference numeral “1 (A)” in FIG. 5 indicates ash processing of the cyclone dust collector hopper (A) of the first system 68. The same applies to the other symbols.

  As shown in FIG. 5, the temperature of the vacuum bag filter 76 is almost constant until the ash of the cyclone dust collector hopper (A) is processed, and the ash of the cyclone dust collector hopper (A) is processed and the vacuum bag filter 76 is processed. When the ash is conveyed to the filter 76, the temperature of the vacuum bag filter 76 rises, for example, from about 90 ° C to about 95 ° C. However, when the ash of the electric dust collector hopper (A) is processed next to the cyclone dust collector hopper (A), the temperature of the vacuum bag filter 76 drops to, for example, about 60 ° C. After that, even if the ash of the cyclone dust collector hopper (B) is treated, the temperature of the vacuum bag filter 76 rises to, for example, about 100 ° C., but the ash of the electric dust collector hopper (B) is treated next. The temperature drops again. Next, after the treatment of all the economizer hoppers 55 provided in the fifth system 72, the ash treatment of the cyclone dust collector hopper 63 and the electrostatic dust collector hopper 62 is alternately performed again. To a peak of about 120 ° C., and the temperature does not rise further. Further, by not performing the ash treatment of all the cyclone dust collector hoppers 63 of the first system 68 in succession, by interposing the ash treatment of the hoppers of the other systems in between, the time to be transferred to the vacuum bag filter 76 is reduced. A bias in the amount of ash per hit can be suppressed.

  On the other hand, in the comparative example as shown in FIGS. 6 and 7, the temperature of the vacuum bag filter 76 becomes higher. In the comparative example, as shown in FIG. 6, all the hoppers provided in the same system are continuously processed, and when the ash treatment of all the hoppers of one system is completed, the ash treatment of the next system is performed. It is transitioning. In such a processing method, as shown by the chain double-dashed line in FIG. 7, for example, when the processing of all the cyclone dust collector hoppers 63 provided in the first system 68 in which the amount of heat of ash is large is performed, the vacuum bag filter is The temperature of 76 rises, for example, to near 160 ° C.

  From the above, it is understood that the ash treatment system 59 according to the present embodiment can suppress the temperature rise of the vacuum bag filter 76 as compared with the comparative example.

  A method of suppressing burning of the filter cloth 85 by using a high-temperature filter cloth having excellent heat resistance for the vacuum bag filter 76 may be considered. However, the filter cloth for high temperature becomes expensive accordingly. According to the present embodiment, since the temperature rise of the vacuum bag filter 76 can be suppressed, it is not necessary to use a high temperature filter cloth, and a general filter cloth can be used. Therefore, the vacuum bag filter 76 can be constructed at low cost. A general filter cloth can withstand up to about 130 ° C., for example. In the ash treatment system 59 of the present embodiment, the temperature of the vacuum bag filter 76 does not reach 130 ° C. as shown by the chain double-dashed line in FIG. 5, so even if a general filter cloth is used, burnout of the filter cloth is suppressed. can do.

  Moreover, since the temperature rise of the vacuum bag filter 76 can be suppressed, the environment in which the filter cloth 85 is used is improved. Therefore, the deterioration of the filter cloth 85 can be suppressed and the life can be improved.

[Modification]
In the configuration of the above embodiment, after the ash of the electrostatic precipitator hopper 62 provided in the second system 69 is processed, cooling air is circulated in the transfer pipe 66 to cool the vacuum bag filter 76. Air may be supplied. That is, between the ash treatment of the electric dust collector hopper (A) and the ash treatment of the cyclone dust collector hopper (B), and between the ash treatment of the electric dust collector hopper (C) and the ash treatment of the cyclone dust collector hopper (D). The cooling air may be supplied during the period.

  By doing so, the vacuum bag filter 76 can be cooled by the cooling air as well, so that the temperature rise of the vacuum bag filter 76 can be further suppressed.

  As the timing of supplying the cooling air, it may be possible to supply the cooling air after the ash of the cyclone dust collector hopper 63 having the largest amount of heat is processed. However, the ash having a smaller heat amount effectively absorbs the heat than the ash having a smaller heat amount than the cooling air, and thus the cooling effect of the vacuum bag filter 76 is higher. Therefore, the ash of the cyclone dust collector hopper 63 is treated and then the ash of the cyclone dust collector hopper 63 is treated, and then the ash of the electric dust collector hopper 62 is treated. It is possible to cool the vacuum bag filter 76 more quickly.

  Further, in the above modification, the cooling air may be dried by preheating the cooling air with the first air preheater 68e or the like. With such a configuration, it is possible to suppress the occurrence of drain inside the transfer pipe 66. By suppressing the generation of drain, it is possible to suppress clogging of the transport pipe 66 due to ash containing water.

It should be noted that the present invention is not limited to the invention according to the above-described embodiment and the above-described modified examples, and can be appropriately modified without departing from the scope of the invention.
For example, the order of processing each hopper is not limited to the above embodiment. The hopper with a small amount of heat may be processed after the hopper with a large amount of heat, for example, after the cyclone dust collector hopper (A) is processed with the electric dust collector hopper (A), the air preheater hopper (A) is then processed. The processing of the economizer hopper (A) and the denitration hopper (A) may be sequentially performed.

  Further, in the above-described embodiment, an example in which the ash treatment device 75 is applied to the thermal power plant 1 in which exhaust gas generated in the combustion device 12 and subjected to heat exchange is completely discharged from the chimney 54 to the atmosphere has been described. Not limited to. For example, the ash treatment device 75 may be applied to the thermal power plant 1 that is provided with an exhaust gas recirculation system that extracts a part of the exhaust gas from a midway position of the exhaust gas flow and returns the extracted exhaust gas to the combustion device 12. In the thermal power plant 1 to which the exhaust gas recirculation system is applied, the ash captured by the cyclone dust collector 61 is likely to reach a high temperature. Therefore, by applying the ash treatment system 59 according to the present embodiment, it is possible to suppress the temperature rise of the vacuum bag filter 76, so even in the thermal power plant 1 to which the exhaust gas recirculation system is applied, An inexpensive general filter cloth can be used without using an expensive filter cloth for high temperature.

1: Thermal power plant (power plant)
10: pulverized coal burning boiler 45: economizer 46: economizer 47: economizer 49: air preheater 50: denitration device 51: electrostatic precipitator (second device)
53: desulfurization device 55: economizer hopper 59: ash treatment system 60: ash discharge system 61: cyclone dust collector (first device)
62: Electric dust collector hopper (second system hopper)
63: Cyclone dust collector hopper (first system hopper)
64: denitration device inlet hopper 65: air preheater hopper 66: transfer pipe 67: vacuum suction blower 68: first system 68a: first transfer pipe 68b: first ash intake valve 68c: first system switching valve 68d: first Suction port 69: Second system 70: Third system 71: Fourth system 72: Fifth system 75: Ash treatment device 76: Vacuum bag filter 77: Backwash air injection device 78: Fly ash tank 79: Case 80 : Collection part 82: Cylindrical part 83: Reduced diameter part 84: Carrier gas discharge pipe 85: Filter cloth 89: Supply device 91: Backwash air pipe 92: Backwash air valve 93: Ash discharge pipe 94: Ash discharge Piping valve 100: Control device (control unit)
110: Transport vehicle

Claims (7)

An ash processing device for processing ash,
A plurality of devices for capturing the ash, including a first device and a second device;
A first system that has a plurality of first system hoppers that store the ash captured by the first device, and transports the ash discharged from the first system hopper to the ash processing device; and a second system that captures the ash. A plurality of systems including at least one second system hopper that stores the ash, and a second system that conveys the ash discharged from the second system hopper to the ash processing device;
After discharging and transporting the ash stored in the first system hopper in a state where at least one of the first system hopper is not discharging and transporting the stored ash, the ash stored in the first system hopper is stored next. An ash processing system including: a control unit that selects the target for discharging and transporting the existing ash in the second system hopper.   The ash according to claim 1, wherein a value of a product of a temperature and an amount of ash stored in the first system hopper is larger than a value of a product of a temperature and an amount of ash stored in the second system hopper. Processing system. The plurality of the systems has a system other than the first system and the second system,
The ash processing system according to claim 2, wherein the value of the product of the temperature and the amount of ash stored in the first system hopper is the largest among the hoppers included in the plurality of systems. The plurality of the systems has a system other than the first system and the second system,
The ash processing system according to claim 2 or 3, wherein the second system hopper has the smallest product value of the temperature and the amount of stored ash among the hoppers of the plurality of systems.   The ash processing system according to any one of claims 2 to 4, wherein after the ash stored in the second system hopper is discharged and conveyed, cooling air is supplied to the ash processing apparatus. An ash treatment system according to any one of claims 1 to 5,
And a combustion device that generates combustion gas by burning a carbon-containing solid fuel,
The ash treatment system is a power plant that treats ash contained in the combustion gas. A first step of discharging and transporting the ash stored in one of the plurality of first system hoppers for storing the ash captured by the first device;
After the first step, the ash stored in at least one of the first system hoppers is not discharged and conveyed, and is stored in the second system hopper that stores the ash captured by the second device. A second step of discharging and transporting the ash that is being stored, and controlling the ash processing system.

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