WO2024034349A1

WO2024034349A1 - Biomass grinding system and operating method for biomass grinding system

Info

Publication number: WO2024034349A1
Application number: PCT/JP2023/026628
Authority: WO
Inventors: 祐貴木谷; 寛貴中島; 聡太朗山口; 雅之加藤
Original assignee: 三菱重工業株式会社; 三菱パワー株式会社
Priority date: 2022-08-09
Filing date: 2023-07-20
Publication date: 2024-02-15
Also published as: JP2024024168A

Abstract

Provided is a boiler system (100) comprising: a biomass mill (10) that grinds a biomass fuel; a boiler (20) that combusts the biomass fuel ground by the biomass mill (10) in a combustion device (22) to generate vapor; an air preheater (30) that heats air by means of exhaust gas discharged from the boiler (20); a first air supply path (50) that supplies the heated air heated by the air preheater (30) to the biomass mill (10); a first branch supply path (51) that branches part of the heated air from the first air supply path (50); and a furnace bottom ash processing facility (40) for using the heated air supplied from the first branch supply path (51) to dry a non-combusted biomass fuel discharged from the boiler (20), and supplying the resultant to the combustion device (22) again.

Description

Biomass grinding system and how to operate the biomass grinding system

The present disclosure relates to a biomass grinding system and a method of operating a biomass grinding system.

Conventionally, a device is known in which coal is pulverized in a mill and supplied to a boiler through a burner (for example, see Patent Document 1). In Patent Document 1, unburned materials are collected from the bottom of a boiler and put into a mill, and the pulverized unburned materials are sent to the boiler through a burner, thereby reusing the unburned materials as fuel.

Patent No. 4861318

However, Patent Document 1 uses only coal (pulverized coal fuel) as a fuel, and does not take into account the reduction in boiler efficiency when using biomass fuel or co-firing biomass fuel and pulverized coal fuel. In a boiler designed to use pulverized coal fuel obtained by pulverizing coal, when using biomass fuel or co-firing biomass fuel and pulverized coal fuel, the ash content in the fuel is lower than when only pulverized coal fuel is burned. Since the total amount is smaller, there is an advantage that the total amount of bottom ash deposited at the bottom of the boiler furnace is reduced. On the other hand, when biomass fuel or biomass fuel and pulverized coal fuel are co-fired, the total mass of unburned fuel contained in the bottom ash increases, and the boiler efficiency decreases due to the increase in unburned fuel (unburned (increased losses).

In addition, primary air heated by boiler exhaust gas is used to dry the fuel in the crusher, but biomass fuel has less moisture in the fuel than pulverized coal fuel, so the amount of heat required to dry the fuel is lower. The temperature of the primary air is sometimes set lower than that of pulverized coal fuel, and in consideration of the ignitability of biomass fuel, the amount of heat recovered from exhaust gas decreases and the boiler efficiency decreases. (exhaust gas loss increases).

The present disclosure has been made in view of these circumstances, and provides a biomass crushing system and a biomass crushing system that can improve boiler efficiency when generating steam in a boiler by burning biomass fuel in a combustion device. The purpose is to provide a method for operating a grinding system.

In order to solve the above problems, the present disclosure employs the following means.
The biomass crushing system according to the present disclosure includes a first crushing device that crushes biomass fuel, a boiler that burns the biomass fuel crushed by the first crushing device in a combustion device to generate steam, and a boiler that generates steam by burning the biomass fuel crushed by the first crushing device. an air preheater that heats air with exhaust gas; a first air supply path that supplies the heated air heated by the air preheater to the first crushing device; a first branch supply path for branching the portion, and a first branch supply path for drying the unburned biomass fuel discharged from the boiler with the heated air supplied from the first branch supply path and supplying the dried biomass fuel to the combustion device again. A resupply section.

A method of operating a biomass crushing system according to the present disclosure includes: a first crusher that crushes biomass fuel; a boiler that burns the biomass fuel crushed by the first crusher in a combustion device to generate steam; A method of operating a biomass crushing system comprising: a second crushing device for crushing the unburned biomass fuel discharged from the boiler, the method comprising: passing the unburned biomass fuel discharged from the boiler to the second crushing device; The method includes a conveyance step of conveying the fuel, and a resupply step of again supplying the unburned biomass fuel crushed by the second crusher to the combustion device.

According to the present disclosure, it is possible to provide a biomass crushing system that can improve boiler efficiency when burning biomass fuel in a combustion device to generate steam in a boiler, and a method for operating the biomass crushing system.

1 is a diagram showing a schematic configuration of a boiler system according to a first embodiment of the present disclosure. It is a flowchart which shows the start-up operation of the bottom ash processing equipment of a 1st embodiment. It is a flowchart which shows the stop operation of the bottom ash processing equipment of a 1st embodiment. FIG. 2 is a diagram showing a schematic configuration of a boiler system according to a second embodiment of the present disclosure. FIG. 3 is a diagram showing a schematic configuration of a boiler system according to a third embodiment of the present disclosure. It is a diagram showing a schematic configuration of a boiler system according to a fourth embodiment of the present disclosure. It is a diagram showing a schematic configuration of a boiler system according to a fifth embodiment of the present disclosure.

[First embodiment]
Below, a boiler system (biomass crushing system) 100 according to a first embodiment of the present disclosure will be described with reference to FIG. 1. As shown in FIG. 1, the boiler system 100 of this embodiment includes a biomass mill (first pulverizer) 10, a biomass fuel storage section 15, a boiler 20, an air preheater 30, and a bottom ash processing equipment ( re-supply section) 40, first air supply path 50, first branch supply path 51, second air supply path (non-heated air supply path) 60, second branch supply path 61, forced draft fan 70 , a primary ventilation fan 80 , and a control device 90 .

The boiler system 100 of this embodiment pulverizes biomass fuel stored in a biomass fuel storage section 15 in a biomass mill 10, and combusts the pulverized biomass fuel in a boiler 20 to generate steam. The air preheater 30 heats the air supplied by the primary ventilation fan 80 using the exhaust gas G discharged from the boiler 20. The heated air heated by the air preheater 30 is supplied to the biomass mill 10 via the first air supply path 50 and is also supplied to the bottom ash processing equipment 40 via the first branch supply path 51. The bottom ash processing equipment 40 is a facility for pulverizing the bottom ash containing unburned biomass fuel discharged from the boiler 20 and supplying it to the boiler 20 again.

Here, biomass fuel refers to renewable organic resources derived from living organisms, such as thinned wood, waste wood, driftwood, grass, waste, sludge, and recycled fuels made from these materials (pellets and chips). ), and is not limited to what is presented here. Since biomass fuel takes in carbon dioxide during the growth process of biomass, it is considered carbon neutral and does not emit carbon dioxide, which is a global warming gas, and various uses are being considered for its use.

The biomass mill 10 is a device that crushes biomass fuel stored in the biomass fuel storage section 15. The biomass mill 10, for example, rotates a grinding table. Biomass fuel sandwiched between a crushing table and a plurality of crushing rollers is crushed. The biomass mill 10 dries the biomass fuel using heated air supplied from the first air supply path 50 , classifies the biomass fuel to a predetermined particle size or less, and supplies the biomass fuel to the biomass fuel supply path 17 . The biomass fuel having a predetermined particle size or less supplied to the biomass fuel supply path 17 is supplied to the boiler 20 .

The biomass mill 10 according to the present disclosure dries the pulverized biomass fuel by blowing pressurized air (primary air) into the biomass mill 10 by the primary ventilator 80 and transports it to the furnace 21 of the boiler 20. This is a so-called pressurized mill. The pressure inside the housing of the biomass mill 10 is higher than the outside (atmospheric) pressure.

The boiler 20 is a device that uses a combustion device 22 to combust the biomass fuel pulverized by the biomass mill 10, and exchanges the heat generated by this combustion with feed water and steam to generate superheated steam. The boiler 20 includes a furnace 21 , a combustion device 22 , a superheater 23 , a reheater 24 , and a coal saver 25 . The boiler 20 burns biomass fuel in a combustion device 22, and combines combustion gas generated in a furnace 21 with water and steam flowing through a heat exchanger (superheater 23, reheater 24, and economizer 25). Allow heat exchange between the two.

A combustion device 22 is provided in the middle of the furnace 21 in the height direction HD. The combustion device 22 includes a plurality of burners 22a and a wind box 22b that supplies combustion air to the burners 22a. Although FIG. 1 shows an example in which the biomass fuel supply path 17 is connected to one of the plurality of burners 22a, the biomass fuel supply path 17 may be branched and connected to each burner 22a. The burner 22a above the burner 22a connected to the biomass fuel supply path 17 is connected to a second supply path 47, which will be described later.

In FIG. 1, the piping to which each burner 22a is connected is omitted, except for the burner 22a connected to the biomass fuel supply path 17 and the burner 22a connected to the second supply path 47. The boiler system 100 shown in FIG. 1 includes a biomass mill 10 and another mill (not shown) different from the mill 41 described below. When co-combusting biomass fuel and pulverized coal fuel, at least one of the other mills pulverizes another solid fuel such as coal, which has a higher calorific value than the biomass fuel. Solid fuel pulverized by other mills is supplied to each burner 22a.

In addition to the biomass mill 10 and the mill 41, the boiler system 100 shown in FIG. It may be an aspect. For example, the boiler system 100 may be a biomass fuel-only combustion system that includes one or more biomass mills 10 and a mill 41 and burns only biomass fuel.

As shown in FIG. 1, a furnace bottom portion 21a is provided below the furnace 21 in the height direction HD. The furnace bottom 21a is immersed in a conveyor 43 filled with a cooling medium such as water, and the inside of the furnace 21 is isolated from the outside air. Of the biomass fuel supplied to the furnace 21, unburned biomass fuel and combustion ash that were not burned by the combustion device 22 fall to the furnace bottom 21a and are cooled by a cooling medium. As described above, the bottom ash processing equipment 40 of this embodiment includes a wet conveyor 43 that cools unburned biomass fuel and combustion ash with a cooling medium.

The air preheater 30 is a device that heats air using exhaust gas G discharged from the furnace 21 of the boiler 20. As shown in FIG. 1, air is supplied to the air preheater 30 from a forced draft fan 70 and a primary draft fan 80, respectively. Further, the air preheater 30 is supplied with exhaust gas G discharged from the furnace 21 via the exhaust gas supply path 26, and heat exchanges with the air supplied from the forced draft fan 70 and the primary draft fan 80. be exposed.

The bottom ash processing equipment 40 is equipment for supplying unburned biomass fuel discharged from the boiler 20 to the combustion device 22 again. The bottom ash processing equipment 40 dries unburned biomass fuel using heated air supplied from a first branch supply path 51 described below. The bottom ash processing equipment 40 includes a mill 41, a storage section 42, a conveyor (unburned fuel conveyance section) 43, a silo 44, a blower 45, a first supply path 46, and a second supply path (unburnt fuel conveyance section). fuel supply path) 47.

The mill 41 is a device that pulverizes the bottom ash BA containing unburned biomass fuel discharged from the bottom 21a of the boiler 20. The amount of unburned biomass fuel discharged from the furnace bottom 21a of the boiler 20 is about 1% to several percent of the total amount of biomass fuel supplied from the biomass fuel supply path 17 to the combustion device 22. Therefore, the mill 41 is smaller and requires less power than the biomass mill 10.

The amount of bottom ash BA that can be crushed by the mill 41 per unit time is sufficiently smaller (for example, 1/10 or less) than the amount of biomass fuel that can be crushed by the biomass mill 10 per unit time. Furthermore, the particle size of the unburned biomass fuel discharged from the mill 41 may be larger than the particle size of the biomass fuel discharged from the biomass mill 10. The bottom ash BA pulverized by the mill 41 is guided to the silo 44 through a first supply path 46 .

The storage unit 42 is a device that stores bottom ash BA containing unburned biomass fuel that is conveyed by the conveyor 43. The amount of bottom ash BA that the storage section 42 supplies to the mill 41 is controlled by a control device 90 .
The conveyor 43 is a device that conveys bottom ash BA containing unburned biomass fuel discharged from the bottom 21 a of the furnace 21 to the storage section 42 .

The silo 44 is a device that temporarily stores the bottom ash BA crushed by the mill 41. The bottom ash BA crushed by the mill 41 is transported to the silo 44 by air supplied from the first branch supply path 51 and the second branch supply path 61, and the air flowing into the silo 44 is installed in the silo 44. It is separated from the pulverized bottom ash BA through the bag filter 44a and released into the atmosphere. The bottom ash BA stored in the silo 44 is supplied to the combustion device 22 of the boiler 20 via the second supply path 47 when the control device 90 operates the blower 45 . Note that since the amount of bottom ash BA supplied from the storage section 42 to the mill 41 is controlled by the control device 90, it is also possible to supply it from the first supply path 46 to the combustion device 22 of the boiler 20 without going through the silo 44. It is possible.

The first air supply path 50 is a flow path that supplies heated air supplied from the primary ventilation fan 80 and heated by the air preheater 30 to the biomass mill 10. The first air supply path 50 is provided with an opening/closing damper 50a and an adjusting damper 50b. The control device 90 opens the opening/closing damper 50a and adjusts the opening degree of the adjustment damper 50b, thereby adjusting the flow rate of heated air guided to the biomass mill 10 via the first air supply path 50.

The first branch supply path 51 is a flow path that branches part of the heated air from the first air supply path 50 and supplies it to the mill 41. The first branch supply path 51 branches part of the heated air from the first air supply path 50 and supplies it to the mill 41 to dry the unburned biomass fuel pulverized by the mill 41 . The first branch supply path 51 is provided with an opening/closing damper 51a and an adjusting damper 51b. The control device 90 opens the opening/closing damper 51a and adjusts the opening degree of the adjustment damper 51b, thereby adjusting the flow rate of heated air guided to the mill 41 via the first branch supply path 51.

The second air supply path 60 is a flow path that supplies unheated air (cold air) that is supplied from the primary ventilation fan 80 and is not heated by the air preheater 30 to the biomass mill 10. The second air supply path 60 is provided with an opening/closing damper 60a and an adjusting damper 60b. The control device 90 opens the opening/closing damper 60a and adjusts the opening degree of the adjustment damper 60b, thereby adjusting the flow rate of cold air guided to the biomass mill 10 via the second air supply path 60.

The second branch supply path 61 is a flow path that branches part of the cold air from the second air supply path 60 and supplies it to the mill 41. The second branch supply path 61 is provided with an opening/closing damper 61a and an adjusting damper 61b. The control device 90 opens the opening/closing damper 61a and adjusts the opening degree of the adjusting damper 61b, thereby adjusting the flow rate of cold air guided to the mill 41 via the second branch supply path 61.

The forced draft fan 70 is a device that forces air (outside air) into the combustion air supply path 71 and supplies it to the wind box 22b of the combustion device 22. The air forced into the combustion air supply path 71 by the forced draft fan 70 is heated by the air preheater 30, and the heated air is supplied to the wind box 22b.

The primary ventilation fan 80 is a device that pushes air (outside air) into the first air supply path 50 and the second air supply path 60 and supplies it to the biomass mill 10. Furthermore, air (outside air) is forced into the first branch supply path 51 and the second branch supply path 61 and is supplied to the mill 41.

The control device 90 is a device that controls each part of the boiler system 100. The control device 90 controls each part of the boiler system 100 by reading and executing a control program from a storage unit (not shown).

Next, the startup operation of the bottom ash processing equipment 40 will be described with reference to FIG. 2. FIG. 2 is a flowchart showing the startup operation of the bottom ash processing equipment 40 of the first embodiment. Each process shown in FIG. 2 is executed by the control device 90. In addition, when performing the process shown in FIG. 2, each part of the boiler system 100, including the biomass mill 10 and the boiler 20, except for the bottom ash processing equipment 40, shall be activated in advance.

In step S101, the control device 90 controls the bottom ash processing equipment 40 to start the bottom ash processing equipment 40. The control device 90 starts each part of the bottom ash processing equipment 40 including the mill 41, the conveyor 43, and the blower 45. By starting the conveyor 43, the bottom ash BA discharged from the bottom 21a of the furnace 21 is supplied to the storage section 42.

In step S102, the control device 90 determines whether the storage amount of bottom ash BA stored in the storage section 42 is equal to or greater than a predetermined amount, and if YES, the process proceeds to step S103, and if NO If so, the determination in step S102 is repeated.

In step S103, the control device 90 opens the opening/closing damper 61a, adjusts the opening degree of the adjustment damper 61b, and opens the second branch supply path 61. The opening degree of the adjustment damper 61b is adjusted according to the target temperature inside the mill 41 and the required amount of air.

In step S104, the control device 90 opens the opening/closing damper 51a, adjusts the opening degree of the adjustment damper 51b, and opens the first branch supply path 51. The opening degree of the adjustment damper 51b is adjusted according to the target temperature inside the mill 41 and the required amount of air.

In step S105, the control device 90 determines whether the inside of the mill 41 has reached the specified temperature, and if YES, the process proceeds to step S106, and if NO, the determination in step S105 is repeatedly executed.

In step S106, the control device 90 starts supplying the bottom ash BA from the storage section 42 to the mill 41, thereby starting the pulverizing operation of the bottom ash BA by the mill 41. The bottom ash BA pulverized by the mill 41 is supplied to the silo 44 via the first supply path 46 .

In step S107, the control device 90 determines whether the boiler 20 has reached a predetermined boiler load at which bottom ash can be input, and if YES, the process proceeds to step S108, and if NO, the process proceeds to step S108. The determination in S107 is repeated.
In step S108, the control device 90 operates the blower 45 and starts supplying the bottom ash BA to the boiler 20.
As described above, the control device 90 starts up the bottom ash processing equipment 40.

Next, with reference to FIG. 3, the stopping operation of the bottom ash processing equipment 40 will be described. FIG. 3 is a flowchart showing the stopping operation of the bottom ash processing equipment 40 of the first embodiment. Each process shown in FIG. 2 is executed by the control device 90.

In step S201, the control device 90 stops the blower 45 and stops supplying the bottom ash BA to the boiler 20.
In step S202, the control device 90 stops the supply of the bottom ash BA to the storage section 42 by the conveyor 43, and switches the discharge destination so that the bottom ash BA is discharged to an outside different from the storage section 42. Note that if there is no mechanism for discharging the bottom ash BA to the outside, steps S202 and S203 may be omitted, and the process may proceed to step S204 in the process of stopping the boiler 20.

In step S203, the control device 90 determines whether the storage amount of bottom ash BA stored in the storage section 42 is less than a predetermined amount, and if YES, the process proceeds to step S204, and if NO, the process proceeds to step S204. If so, the determination in step S203 is repeated.

In step S204, the control device 90 controls the supply amount of bottom ash BA from the storage section 42 to the mill 41 to a specified amount, which is a predetermined minimum amount.

In step S205, the control device 90 sequentially closes the adjustment damper 51b and the opening/closing damper 51a, and blocks the first branch supply path 51. By blocking the first branch supply path 51, only cold air is supplied to the mill 41 from the second branch supply path 61.

In step S206, the control device 90 determines whether the temperature inside the mill 41 has become lower than the specified temperature, and if YES, the process proceeds to step S207, and if NO, it repeatedly executes the determination in step S206.

In step S207, the control device 90 stops supplying the bottom ash BA from the storage section 42 to the mill 41.
In step S208, the control device 90 continues supplying cold air from the second branch supply path 61 to the inside of the mill 41 for a certain period of time, and performs a discharge process (purge process) of the bottom ash BA remaining in the mill 41. .

In step S209, the control device 90 stops the grinding operation by the mill 41.
In step S210, the control device 90 sequentially closes the adjustment damper 61b and the opening/closing damper 61a, and blocks the second branch supply path 61.
As described above, the control device 90 stops the bottom ash processing equipment 40.

The operations and effects of the boiler system 100 of this embodiment described above will be explained.
According to the boiler system 100 of this embodiment, the biomass fuel pulverized by the biomass mill 10 is burned in the combustion device 22, and steam is generated in the boiler 20. Air is heated by the air preheater 30 by the exhaust gas G discharged from the boiler 20, and the heated air is supplied to the biomass mill 10 via the first air supply path 50. The unburned biomass fuel discharged from the boiler 20 is dried by the bottom ash processing equipment 40 using heated air supplied from the first branch supply path 51 and is supplied to the combustion device 22 again.

According to the boiler system 100 of the present embodiment, when pulverizing biomass in the biomass mill 10, the temperature of the heated air (primary air) supplied to the biomass mill 10 is adjusted to take into account the ignitability of the biomass fuel. Even if it is set lower than when pulverizing the fuel, there is no need to significantly reduce the amount of heat recovered from the exhaust gas G in the air preheater 30. This is because a portion of the heated air is used to dry the unburned biomass fuel in the mill 41. Therefore, according to the boiler system 100 of the present embodiment, it is possible to improve the boiler efficiency when biomass fuel is combusted in the combustion device 22 and steam is generated in the boiler 20.

Furthermore, according to the boiler system 100 of the present embodiment, unburned biomass fuel discharged from the boiler 20 is conveyed to the mill 41 via the conveyor 43 and the storage section 42, and is pulverized by the mill 41. According to the boiler system 100 of this embodiment, the biomass fuel is combusted in the combustion device 22 by drying the unburned biomass fuel pulverized by the mill 41 with the heated air supplied from the first branch supply path 51. Thus, the boiler efficiency when generating steam in the boiler 20 can be improved.

Moreover, according to the boiler system 100 of this embodiment, the unheated air supplied to the biomass mill 10 from the second air supply path 60 is mixed with the heated air supplied to the biomass mill 10 from the first air supply path 50. However, the temperature of the mixture of unheated air and heated air (primary air) introduced into the biomass mill 10 is appropriately adjusted. Further, the unheated air supplied to the mill 41 from the second branch supply path 61 mixes with the heated air supplied to the mill 41 from the first branch supply path 51, and the unheated air guided into the inside of the mill 41. The temperature of the mixture with heated air (primary air) is adjusted appropriately.

Furthermore, according to the boiler system 100 of the present embodiment, the combustion ash generated by the biomass fuel burned in the boiler 20 falls onto the conveyor 43 filled with a cooling medium, and can be cooled by the cooling medium. The unburned biomass fuel comes into contact with the cooling medium on the conveyor 43 and contains the cooling medium, but is dried by heated air supplied from the first branch supply path 51 in the bottom ash processing equipment 40. Ru. Therefore, in the boiler 20 having the wet conveyor 43, unburned biomass fuel can be dried by effectively utilizing the heat recovered by the air preheater 30 from the exhaust gas discharged from the boiler 20.

Furthermore, according to the boiler system 100 of the present embodiment, the biomass fuel pulverized by the biomass mill 10 is burned in the combustion device 22, and steam is generated in the boiler 20. Unburned biomass fuel discharged from the boiler 20 is conveyed to the mill 41 via the conveyor 43 and storage section 42, and is pulverized by the mill 41. The unburned biomass fuel pulverized by the mill 41 is supplied again to the combustion device 22 by the bottom ash processing equipment 40. According to the boiler system 100 of the present embodiment, unburned biomass fuel discharged from the boiler 20 is pulverized by the mill 41 and then supplied to the combustion device 22 again. It can be burned reliably.

According to the boiler system 100 of the present embodiment, in order to directly supply the unburned biomass fuel pulverized by the mill 41 to the combustion device 22, the existing supply that supplies biomass fuel from the biomass mill 10 to the combustion device 22 is used. It does not affect the road.

[Second embodiment]
Next, a boiler system 100A according to a second embodiment of the present disclosure will be described. This embodiment is a modification of the first embodiment, and is the same as the first embodiment except when specifically explained below, and the explanation below will be omitted.

In the boiler system 100 of the first embodiment, the second supply path 47 of the bottom ash processing equipment 40 directly supplies unburned biomass fuel pulverized in the mill 41 to the combustion device 22, or the first supply path 46 directly supplies the unburned biomass fuel pulverized by the mill 41 to the combustion device 22. On the other hand, in the boiler system 100A of the present embodiment, the first supply path 46 of the bottom ash processing equipment 40A feeds the unburned biomass fuel pulverized in the mill 41 into the combustion device 22 with additives. 110. This additive is added to the furnace 21 of the boiler 20 in order to reduce ash adhesion and corrosion to the furnace 21 and heat transfer parts of the boiler 20 when biomass fuel is used. Ash etc. are used.

FIG. 4 is a diagram showing a schematic configuration of a boiler system 100A according to a second embodiment of the present disclosure. As shown in FIG. 4, the boiler system 100A includes an input section 110, a blower 120, and an additive supply path 130. On the other hand, the boiler system 100A does not include the silo 44 and blower 45 of the boiler system 100 of the first embodiment.

The input unit 110 is a device that inputs an additive (for example, coal ash) to the combustion device 22. The control device 90 operates the blower (additive charging device) 120 to supply the additive stored in the charging section 110 to the combustion device 22 via the additive supply path 130. As shown in FIG. 4, in this embodiment, the additive supply path 130 is arranged to join the biomass fuel supply path 17. The additive that has flowed from the additive supply path 130 into the biomass fuel supply path 17 is supplied to the burner 22a of the combustion device 22 together with the biomass fuel supplied from the biomass mill 10.

According to the boiler system 100 of the present embodiment, by adding additives, it is possible to reduce ash adhesion and corrosion to the furnace 21 and heat transfer parts of the boiler 20 when biomass fuel is used. Further, the unburned biomass fuel pulverized by the mill 41 can be appropriately supplied to the combustion device 22 via the input section 110.

In this embodiment, the supply route to the combustion device 22 dedicated to unburned biomass fuel pulverized by the mill 41 can be shared with the additive supply route 130, so there is no effect on the piping arrangement in the existing boiler equipment, and it can be easily modified. , additional installation is possible. Further, since the unburned biomass fuel can be burned in the burner 22a connected to the biomass fuel supply path 17, a unique combustion device for burning the unburned biomass fuel can be made unnecessary.

[Third embodiment]
Next, a boiler system 100B according to a third embodiment of the present disclosure will be described. This embodiment is a modification of the first embodiment, and is the same as the first embodiment except when specifically explained below, and the explanation below will be omitted.

In the boiler system 100 of the first embodiment, the second supply path 47 of the bottom ash processing equipment 40 transfers the unburned biomass fuel pulverized in the mill 41 to the burner to which the biomass fuel is supplied from the biomass fuel supply path 17. The fuel was supplied to another burner 22a different from the burner 22a. In contrast, in the boiler system 100B of the present embodiment, the second supply path 47 of the bottom ash processing equipment 40B joins the unburned biomass fuel pulverized in the mill 41 to the biomass fuel supply path 17. be. Note that, like the first embodiment, since the supply amount of bottom ash BA from the storage section 42 to the mill 41 is controlled by the control device 90, the bottom ash BA is pulverized by the mill 41 from the first supply path 46 without passing through the silo 44. It is also possible to merge the unburned biomass fuel into the biomass fuel supply path 17.

FIG. 5 is a diagram showing a schematic configuration of a boiler system 100B according to a third embodiment of the present disclosure. As shown in FIG. 5, in the boiler system 100B of this embodiment, the second supply path 47 of the bottom ash processing equipment 40B connects the unburned biomass fuel pulverized in the mill 41 to the biomass fuel supply path 17. It is arranged so that The control device 90 causes the bottom ash BA containing unburned biomass fuel stored in the silo 44 to join the biomass fuel supply path 17 from the second supply path 47 by operating the blower 45 . Alternatively, the control device 90 controls the supply amount from the storage section 42 to the mill 41 to transfer the bottom ash BA containing unburned biomass fuel crushed in the mill 41 from the first supply path 46 to the biomass fuel. It is made to merge with the fuel supply path 17.

According to the boiler system 100B of this embodiment, in order to make the unburned biomass fuel pulverized in the mill 41 join the existing biomass fuel supply path 17 that supplies biomass fuel from the biomass mill 10 to the combustion device 22, Unlike the boiler system 100 of the first embodiment, there is no need to newly add a burner 22a that burns unburned biomass fuel to the combustion device 22, so that existing equipment can be easily modified or added.

[Fourth embodiment]
Next, a boiler system 100C according to a fourth embodiment of the present disclosure will be described. This embodiment is a modification of the first embodiment, and is the same as the first embodiment except when specifically explained below, and the explanation below will be omitted.

In the boiler system 100 of the first embodiment, the second supply path 47 of the bottom ash processing equipment 40 directly supplies unburned biomass fuel pulverized in the mill 41 to the combustion device 22, or the first supply path 46 directly supplies the unburned biomass fuel pulverized by the mill 41 to the combustion device 22. In contrast, in the boiler system 100C of the present embodiment, the first supply path 46 of the bottom ash processing equipment 40C guides the unburned biomass fuel pulverized in the mill 41 to the biomass fuel storage section 15. .

FIG. 6 is a diagram showing a schematic configuration of a boiler system 100C according to a fourth embodiment of the present disclosure. As shown in FIG. 6, the boiler system 100C is arranged such that the first supply path 46 of the bottom ash processing equipment 40C guides the unburned biomass fuel pulverized in the mill 41 to the biomass fuel storage section 15. ing. The control device 90 operates the blower 45 to guide the bottom ash BA containing unburned biomass fuel stored in the silo 44 from the first supply path 46 to the biomass fuel storage section 15 .

According to the boiler system 100C of the present embodiment, the biomass fuel supply path 17 is connected in order to guide the unburned biomass fuel pulverized by the mill 41 to the biomass fuel storage section 15 that stores the biomass fuel pulverized by the biomass mill 10. The control operation of the existing fuel supply system including the fuel supply system can be maintained without change.

[Fifth embodiment]
Next, a boiler system 100D according to a fifth embodiment of the present disclosure will be described. This embodiment is a modification of the first embodiment, and is the same as the first embodiment except when specifically explained below, and the explanation below will be omitted.

In the boiler system 100 of the first embodiment, the second supply path 47 of the bottom ash processing equipment 40 directly supplies unburned biomass fuel pulverized in the mill 41 to the combustion device 22. In contrast, in the boiler system 100D of the present embodiment, the second supply path 47 of the bottom ash processing equipment 40D transports the unburned biomass fuel crushed in the mill 41 to the biomass fuel storage section 15. It leads to the biomass fuel conveyor (biomass fuel conveyance section) 18.

FIG. 7 is a diagram showing a schematic configuration of a boiler system 100D according to a fifth embodiment of the present disclosure. As shown in FIG. 7, the boiler system 100D includes a biomass fuel conveyor 18 that conveys biomass fuel to the biomass fuel storage section 15. The boiler system 100D is arranged such that the second supply path 47 of the bottom ash processing equipment 40D guides the unburned biomass fuel pulverized in the mill 41 to the biomass fuel conveyor 18.

The control device 90 operates the blower 45 to guide the bottom ash BA containing unburned biomass fuel stored in the silo 44 from the second supply path 47 to the biomass fuel conveyor 18. The bottom ash BA guided to the biomass fuel conveyor 18 is stored in the biomass fuel storage section 15 together with the biomass fuel.

According to the boiler system 100D of the present embodiment, the unburned biomass fuel pulverized by the mill 41 is guided to the biomass fuel conveyor 18 which conveys the biomass fuel to the biomass fuel storage section 15 where the biomass fuel pulverized by the biomass mill 10 is stored. , the control operation of the existing fuel supply system including the biomass fuel supply path 17 can be maintained without change.

The biomass crushing system described in each embodiment described above can be understood, for example, as follows.
A biomass crushing system (100) according to a first aspect of the present disclosure includes a first crusher (10) that crushes biomass fuel, and a combustion device that burns the biomass fuel crushed by the first crusher to generate steam. a boiler (20) that generates air, an air preheater (30) that heats air with exhaust gas discharged from the boiler, and a first air supply that supplies the heated air heated by the air preheater to the first pulverizer. a supply path (50); a first branch supply path (51) that branches a portion of the heated air from the first air supply path; and a first branch supply path (51) that branches part of the heated air from the first air supply path; A resupply section (40) is provided for drying the heated air supplied from the supply path and supplying the dried air to the combustion device again.

According to the biomass pulverization system according to the first aspect of the present disclosure, the biomass fuel pulverized by the first pulverizer is combusted in the combustion device, and steam is generated in the boiler. Air is heated in the air preheater by exhaust gas discharged from the boiler, and the heated air is supplied to the first crushing device via the first air supply path. The unburned biomass fuel discharged from the boiler is dried by the resupply section using heated air supplied from the first branch supply path, and is supplied again to the combustion device.

According to the biomass pulverization system according to the first aspect of the present disclosure, the temperature of the heated air (primary air) supplied to the first pulverizer is set lower than that of pulverized coal fuel in consideration of the ignitability of the biomass fuel. Even in such cases, it is possible to suppress a decrease in the amount of heat recovered from the exhaust gas in the air preheater. This is because part of the heated air is used to dry the unburned biomass fuel, so the heated air supplied to the first pulverizer prevents the inside of the first pulverizer from becoming too hot. It is. Therefore, according to the biomass crushing system according to the first aspect of the present disclosure, it is possible to improve the boiler efficiency when biomass fuel is burned in the combustion device and steam is generated in the boiler.

The biomass crushing system according to the second aspect of the present disclosure further includes the following configuration in the first aspect. That is, the resupply section includes a second crushing device (41) that crushes the unburned biomass fuel discharged from the boiler, and a second crusher (41) that crushes the unburned biomass fuel discharged from the boiler. an unburnt fuel conveying section (43) for conveying the unburned fuel to the first air supply passage, and the first branch supply passage branches a part of the heated air from the first air supply passage and supplies it to the second crushing device. Then, the unburnt biomass fuel pulverized by the second pulverizer is dried.

According to the biomass crushing system according to the second aspect of the present disclosure, unburned biomass fuel discharged from the boiler is conveyed to the second crushing device by the unburned fuel conveying section, and is crushed by the second crushing device. According to the biomass crushing system according to the second aspect of the present disclosure, the biomass fuel is combusted by drying the unburned biomass fuel crushed by the second crushing device with the heated air supplied from the first branch supply path. Boiler efficiency can be improved when combustion is performed in the device and steam is generated in the boiler.

The biomass crushing system according to the third aspect of the present disclosure further includes the following configuration in the second aspect. That is, a second air supply path (60) supplies unheated air that is not heated by the air preheater to the first crushing device, and a part of the unheated air is branched from the second air supply path to A second branch supply path (61) for supplying to the second crushing device.

According to the biomass crushing system according to the third aspect of the present disclosure, the unheated air supplied from the second air supply path to the first crushing device is replaced by the heated air supplied from the first air supply path to the first crushing device. The temperature of the mixture (primary air) of unheated air and heated air that is mixed with the primary air and introduced into the first pulverizer is adjusted appropriately. Further, the unheated air supplied from the second branch supply path to the second crushing device is mixed with the heated air supplied from the first branch supply path to the second crushing device, and is guided into the second crushing device. The temperature of the mixture of unheated air and heated air (primary air) is adjusted appropriately.

The biomass crushing system according to the fourth aspect of the present disclosure further includes the following configuration in any of the first to third aspects. That is, the boiler includes a wet unburned fuel conveying section (43) that cools the combustion ash of the biomass fuel with a cooling medium.

According to the biomass crushing system according to the fourth aspect of the present disclosure, combustion ash generated by biomass fuel burned in the boiler can be cooled by a cooling medium in the wet unburned fuel conveyance section. The unburned biomass fuel comes into contact with the cooling medium in the unburned fuel conveyance section, so that it contains the cooling medium, but in the resupply section, it is dried by heated air supplied from the first branch supply path. . Therefore, in a boiler having a wet unburned fuel conveyance section, unburned biomass fuel can be dried by effectively utilizing the heat recovered by the air preheater from the exhaust gas discharged from the boiler.

A biomass crushing system according to a fifth aspect of the present disclosure includes: a first crushing device that crushes biomass fuel; a boiler that generates steam by burning the biomass fuel crushed by the first crushing device in a combustion device; a second pulverizer that pulverizes the unburned biomass fuel discharged from the boiler; a transport section that conveys the unburned biomass fuel discharged from the boiler to the second pulverizer; and a second pulverizer. and a resupply section for supplying the unburned biomass fuel, which has been pulverized by the biomass fuel, to the combustion device again.

According to the biomass crushing system according to the fifth aspect of the present disclosure, the biomass fuel crushed by the first crusher is burned in the combustion device, and steam is generated in the boiler. Unburned biomass fuel discharged from the boiler is conveyed to the second crushing device by the unburned fuel conveying section, and is crushed by the second crushing device. The unburned biomass fuel pulverized by the second pulverizer is again supplied to the combustion device by the resupply section. According to the biomass pulverization system according to the fifth aspect of the present disclosure, unburned biomass fuel discharged from the boiler is pulverized by the second pulverizer and then supplied to the combustion device again. It can be reliably burned with a combustion device.

The biomass crushing system according to the sixth aspect of the present disclosure further includes the following configuration in either the second aspect, the third aspect, or the fifth aspect. That is, the resupply section has an unburned fuel supply path (47) that supplies the unburned biomass fuel crushed by the second crusher to the combustion device.

According to the biomass crushing system according to the sixth aspect of the present disclosure, in order to directly supply the unburned biomass fuel crushed by the second crusher to the combustion device, the biomass fuel is transferred from the first crusher to the combustion device. There will be no impact on existing supply routes.

The biomass crushing system according to the seventh aspect of the present disclosure further includes the following configuration in either the second aspect, the third aspect, or the fifth aspect. That is, it includes an input section (110) for inputting additives into the combustion device, and the resupply section guides the unburned biomass fuel crushed by the second crushing device to the input section.

According to the biomass crushing system according to the seventh aspect of the present disclosure, adhesion of combustion ash to the furnace of the boiler due to burning biomass fuel can be appropriately reduced by adding an additive. Further, the unburned biomass fuel pulverized by the second pulverizer can be appropriately supplied to the combustion device via the input section. In this embodiment, the supply route to the combustion device 22 dedicated to unburned biomass fuel pulverized by the mill 41 can be shared with the additive supply route 130, so there is no impact on the piping arrangement in the existing boiler equipment, and it can be easily modified. Additional installation is possible.
Moreover, since the unburned biomass fuel can be burned in the burner 22a connected to the biomass fuel supply path 17, a unique combustion device for burning the unburned biomass fuel can be made unnecessary.

The biomass crushing system according to the eighth aspect of the present disclosure further includes the following configuration in either the second aspect, the third aspect, or the fifth aspect. That is, the re-supply section includes a biomass fuel supply path (17) that supplies the biomass fuel crushed by the first crushing device to the combustion device, and the re-supply section supplies the unburned biomass crushed by the second crushing device. The fuel is merged into the biomass fuel supply path.

According to the biomass pulverization system according to the eighth aspect of the present disclosure, unburned biomass fuel pulverized by the second pulverizer is merged into an existing fuel supply path that supplies biomass fuel from the first pulverizer to the combustion device. Since there is no need to add a new burner for burning unburned biomass fuel to the combustion equipment, existing equipment can be easily modified or added.

The biomass crushing system according to the ninth aspect of the present disclosure further includes the following configuration in either the second aspect, the third aspect, or the fifth aspect. That is, the first pulverizer includes a biomass fuel storage section (15) that stores the biomass fuel pulverized, and the resupply section stores the unburned biomass fuel pulverized by the second pulverizer into the biomass fuel. Lead to fuel storage.

According to the biomass pulverization system according to the ninth aspect of the present disclosure, in order to guide the unburned biomass fuel pulverized by the second pulverizer to the biomass fuel storage section that stores the biomass fuel pulverized by the first pulverizer, The control operation of the existing fuel supply system can be maintained without modification.

The biomass crushing system according to the tenth aspect of the present disclosure further includes the following configuration in the second aspect, third aspect, or fifth aspect. That is, the first crushing device includes a biomass fuel storage section (42) that stores the biomass fuel crushed by the first crushing device, and a biomass fuel conveyance section (43) that conveys the biomass fuel to the biomass fuel storage section, and The resupply section guides the unburned biomass fuel pulverized by the second pulverizer to the biomass fuel transport section.

According to the biomass pulverization system according to the tenth aspect of the present disclosure, the unburned biomass fuel pulverized by the second pulverizer is sent to the biomass fuel transport section that transports the biomass fuel to the biomass fuel storage section that stores the biomass fuel. Therefore, the control operation of the existing fuel supply system can be maintained unchanged.

A method for operating a biomass pulverization system according to an eleventh aspect of the present disclosure includes a first pulverizer that pulverizes biomass fuel, and a boiler that combusts the biomass fuel pulverized by the first pulverizer in a combustion device to generate steam. an air preheater that heats air with exhaust gas discharged from the boiler; a first air supply path that supplies the heated air heated by the air preheater to the first pulverizer; and the first air supply. A method of operating a biomass crushing system comprising: a first branch supply path for branching a part of the heated air from the boiler; The method includes a drying step of drying using the supplied heated air, and a resupply step of again supplying the unburnt biomass fuel dried in the drying step to the combustion device.

According to the operating method of the biomass crushing system according to the eleventh aspect of the present disclosure, the biomass fuel crushed by the first crusher is burned in the combustion device, and steam is generated in the boiler. Air is heated in the air preheater by exhaust gas discharged from the boiler, and the heated air is supplied to the first crushing device via the first air supply path. Unburned biomass fuel discharged from the boiler is dried by heated air supplied from the first branch supply path in a drying process, and is again supplied to the combustion device in a resupply process.

According to the operating method of a biomass pulverization system according to the eleventh aspect of the present disclosure, the temperature of the heated air (primary air) supplied to the first pulverizer is set in consideration of the ignitability of the biomass fuel compared to that of pulverized coal fuel. Even if it is set low, there is no need to significantly reduce the amount of heat recovered from the exhaust gas in the air preheater. This is because a portion of the heated air is used to dry the unburned biomass fuel, so the heated air supplied to the first pulverizer prevents the first pulverizer from reaching an excessively high temperature. . Therefore, according to the operating method of the biomass crushing system according to the first aspect of the present disclosure, it is possible to improve the boiler efficiency when biomass fuel is burned in the combustion device and steam is generated in the boiler.

A method for operating a biomass pulverization system according to a twelfth aspect of the present disclosure includes a first pulverizer that pulverizes biomass fuel, and a boiler that combusts the biomass fuel pulverized by the first pulverizer in a combustion device to generate steam. and a second pulverizer that pulverizes the unburned biomass fuel discharged from the boiler, the method of operating a biomass pulverization system comprising: and a resupply step of supplying the unburned biomass fuel crushed by the second crushing device to the combustion device again.

According to the method of operating a biomass crushing system according to the twelfth aspect of the present disclosure, the biomass fuel crushed by the first crusher is burned in the combustion device, and steam is generated in the boiler. Unburned biomass fuel discharged from the boiler is conveyed to the second pulverizer through a conveyance process, and is pulverized by the second pulverizer. The unburned biomass fuel pulverized by the second pulverizer is again supplied to the combustion device in a re-supply step. According to the method of operating a biomass crushing system according to the eleventh aspect of the present disclosure, unburned biomass fuel discharged from the boiler is crushed by the second crusher and then supplied to the combustion device again. Biomass fuel can be reliably burned in a combustion device.

10 Biomass mill (first crushing device)
15 Biomass fuel storage section 17 Biomass fuel supply path 18 Biomass fuel conveyor 20 Boiler 21 Furnace 21a Furnace bottom 22 Combustion device 22a Burner 22b Wind box 23 Superheater 24 Reheater 25 Economizer 30

Air preheater

40, 40A, 40B, 40C, 40D Bottom ash processing equipment 41 Mill 42 Storage section 43 Conveyor 44 Silo 45 Blower 46 First supply path 47 Second supply path 50 First

air supply path

50a, 51a, 60a, 61a Opening/

closing damper

50b, 51b, 60b, 61b Adjustment damper 51 First branch supply passage 60 Second air supply passage 61 Second branch supply passage 70 Forced draft fan 71 Combustion air supply passage 80 Primary draft fan 90

Control device

100, 100A, 100B, 100C, 100D Boiler system 110 Input part 120 Blower 130 Additive supply path BA Hearth ash G Exhaust gas HD Height direction

Claims

a first crusher that crushes biomass fuel;
a boiler that generates steam by burning the biomass fuel crushed by the first crushing device in a combustion device;
an air preheater that heats air with exhaust gas discharged from the boiler;
a first air supply path that supplies heated air heated by the air preheater to the first pulverizer;
a first branch supply path that branches part of the heated air from the first air supply path;
A biomass pulverization system comprising: a resupply section for drying the unburned biomass fuel discharged from the boiler with the heated air supplied from the first branch supply path and supplying the dried biomass fuel to the combustion device again.
The resupply section includes:
a second crushing device that crushes the unburned biomass fuel discharged from the boiler;
an unburned fuel transport unit that transports the unburned biomass fuel discharged from the boiler to the second crushing device,
The first branch supply path branches part of the heated air from the first air supply path and supplies it to the second pulverizer, and the unburnt biomass fuel is pulverized by the second pulverizer. The biomass grinding system according to claim 1, which dries the biomass grinding system.
a second air supply path that supplies unheated air that is not heated by the air preheater to the first crushing device;
The biomass pulverization system according to claim 2, further comprising a second branch supply path that branches part of the unheated air from the second air supply path and supplies the branched air to the second pulverizer.
The biomass pulverization system according to any one of claims 1 to 3, wherein the boiler includes a wet unburned fuel conveying section that cools the combustion ash of the biomass fuel with a cooling medium.
a first crusher that crushes biomass fuel;
a boiler that generates steam by burning the biomass fuel crushed by the first crushing device in a combustion device;
a second crushing device that crushes the unburned biomass fuel discharged from the boiler;
an unburned fuel transport unit that transports the unburned biomass fuel discharged from the boiler to the second pulverizer;
A biomass crushing system comprising: a resupply unit for supplying the unburned biomass fuel crushed by the second crusher to the combustion device again.
Any one of claims 2, 3, and 5, wherein the resupply section has an unburned fuel supply path that supplies the unburned biomass fuel pulverized by the second pulverizer to the combustion device. The biomass grinding system described in section.
comprising an input section for inputting an additive into the combustion device,
The biomass crushing system according to any one of claims 2, 3, and 5, wherein the resupply unit guides the unburned biomass fuel crushed by the second crusher to the input unit.
comprising a biomass fuel supply path for supplying the biomass fuel crushed by the first crushing device to the combustion device,
The biomass according to any one of claims 2, 3, and 5, wherein the re-supply unit merges the unburned biomass fuel crushed by the second crusher into the biomass fuel supply path. Grinding system.
a biomass fuel storage section for storing the biomass fuel crushed by the first crushing device;
The biomass pulverization according to claim 2, wherein the resupply section guides the unburned biomass fuel pulverized by the second pulverizer to the biomass fuel storage section. system.
a biomass fuel storage section that stores the biomass fuel crushed by the first crushing device;
a biomass fuel transport unit that transports the biomass fuel to the biomass fuel storage unit,
The biomass pulverizer according to claim 2, wherein the resupply section guides the unburned biomass fuel pulverized by the second pulverizer to the biomass fuel transport section. system.
a first crushing device that crushes biomass fuel; a boiler that generates steam by burning the biomass fuel crushed by the first crushing device in a combustion device; and air preheating that heats air with exhaust gas discharged from the boiler. a first air supply path that supplies the heated air heated by the air preheater to the first crushing device; and a first branch supply path that branches part of the heated air from the first air supply path. A method of operating a biomass crushing system comprising:
a drying step of drying the unburned biomass fuel discharged from the boiler with the heated air supplied from the first branch supply path;
A method for operating a biomass pulverization system, comprising: a resupply step of again supplying the unburnt biomass fuel dried in the drying step to the combustion device.
a first crusher that crushes biomass fuel; a boiler that burns the biomass fuel crushed by the first crusher to generate steam in a combustion device; and crushes the unburned biomass fuel discharged from the boiler. A method of operating a biomass crushing system comprising: a second crushing device;
a conveyance step of conveying the unburned biomass fuel discharged from the boiler to the second crushing device;
A method of operating a biomass crushing system, comprising: a resupply step of again supplying the unburnt biomass fuel crushed by the second crusher to the combustion device.