TW202419779A - Biomass grinding system and operating method for biomass grinding system - Google Patents

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 crushing system and operation method of biomass crushing system

The present invention relates to a biomass crushing system and an operation method of the biomass crushing system.

In the past, there is a known device that pulverizes coal with a grinder and supplies it to a boiler through a burner (for example, see Patent Document 1). In Patent Document 1, unburned matter is recovered from the bottom of the boiler and fed into the grinder, and the pulverized unburned matter is sent to the boiler through a burner, thereby using the unburned matter as fuel again. [Prior Technical Document] [Patent Document]

[Patent Document 1] Japanese Patent No. 4861318

[The problem the invention is trying to solve]

However, in Patent Document 1, only coal (pulverized coal fuel) is used as fuel, and the use of biomass fuel or the reduction in boiler efficiency when the biomass fuel and pulverized coal fuel are mixed is not considered. In a boiler designed to use pulverized coal fuel obtained by pulverizing coal, the total amount of ash in the fuel becomes smaller when biomass fuel is used or when the biomass fuel and pulverized coal fuel are mixed, compared with the case of burning only pulverized coal fuel, so there is an advantage that the total amount of bottom ash accumulated at the bottom of the furnace of the boiler is reduced. On the other hand, when biomass fuel or biomass fuel is mixed with pulverized coal fuel, the total mass of unburned fuel contained in the bottom ash will increase, which will increase the amount of unburned fuel and reduce the boiler efficiency (the loss of unburned components will increase).

Furthermore, in order to dry the fuel, the pulverizing device uses primary air that has been heated by the exhaust gas of the boiler. However, biomass fuel contains less water than pulverized coal fuel, so the heat used to dry the fuel is less than that of pulverized coal fuel. In addition, considering the ignition properties of biomass fuel, the temperature of the primary air is sometimes set lower than that of pulverized coal fuel. In this case, the amount of heat recovered from the exhaust gas will decrease, resulting in a decrease in boiler efficiency (exhaust gas loss will increase).

The present invention is completed in view of the above situation, and its purpose is to provide a biomass crushing system and an operating method of the biomass crushing system, which can improve the boiler efficiency when the combustion device burns biomass fuel and generates steam in the boiler. [Technical means for solving the problem]

In order to solve the above problems, the present invention adopts the following means. The biomass pulverizing system of the present invention comprises: a first pulverizing device, which pulverizes biomass fuel; a boiler, which burns the biomass fuel pulverized by the first pulverizing device in a combustion device to generate steam; an air preheater, which heats air by exhaust gas discharged from the boiler; a first air supply path, which supplies heated air heated by the air preheater to the first pulverizing device; a first branch supply path, which branches a part of the heated air from the first air supply path; and a resupply section, which dries the unburned biomass fuel discharged from the boiler by the heated air supplied from the first branch supply path and supplies it to the combustion device again.

The operating method of the biomass pulverizing system of the present invention comprises: a first pulverizing device for pulverizing biomass fuel; a boiler for burning the aforementioned biomass fuel pulverized by the aforementioned first pulverizing device in a combustion device to generate steam; and a second pulverizing device for pulverizing the aforementioned unburned biomass fuel discharged from the aforementioned boiler. The operating method of the biomass pulverizing system comprises: a transporting process for transporting the aforementioned unburned biomass fuel discharged from the aforementioned boiler to the aforementioned second pulverizing device; and a resupply process for resupplying the aforementioned unburned biomass fuel pulverized by the aforementioned second pulverizing device to the aforementioned combustion device. [Effects of the invention]

According to the present invention, a biomass pulverizing system and an operating method of the biomass pulverizing system can be provided, which can improve the boiler efficiency when the combustion device burns biomass fuel and generates steam in the boiler.

[First implementation form]

Hereinafter, a boiler system (biomass pulverizing system) 100 of the first embodiment of the present invention will be described with reference to FIG1 . As shown in FIG1 , the boiler system 100 of the present embodiment includes: a biomass grinder (first pulverizing device) 10, a biomass fuel storage unit 15, a boiler 20, an air preheater 30, a bottom ash treatment device (resupply unit) 40, a first air supply path 50, a first branch supply path 51, a second air supply path (non-heating air supply path) 60, a second branch supply path 61, a blowing ventilator 70, a primary ventilator 80, and a control device 90.

The boiler system 100 of this embodiment grinds the biomass fuel stored in the biomass fuel storage unit 15 by the biomass grinder 10, and burns the grinded biomass fuel in the boiler 20 to generate steam. The air preheater 30 heats the air supplied by the primary ventilator 80 by the exhaust gas G discharged from the boiler 20. The heated air heated by the air preheater 30 is supplied to the biomass grinder 10 through the first air supply path 50, and is supplied to the bottom ash processing equipment 40 through the first branch supply path 51. The bottom ash processing equipment 40 is a device for grinding 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 from living organisms, such as thinnings, waste wood, driftwood, grass, garbage, sludge, and renewable fuels (pellets or fragments) made from these materials, but is not limited to those mentioned here. Biomass fuel absorbs carbon dioxide during the cultivation process of biomass, so it is considered carbon neutral and does not emit carbon dioxide that becomes global warming gas, so its use has been discussed in many ways.

The biomass grinder 10 is a device for pulverizing the biomass fuel stored in the biomass fuel storage unit 15. The biomass grinder 10, for example, rotates the pulverizing platform. The biomass fuel sandwiched between the pulverizing platform and the plurality of pulverizing rollers is pulverized. The biomass grinder 10 dries the biomass fuel and screens it into a predetermined particle size or less by the heated air supplied from the first air supply path 50, and supplies it to the biomass fuel supply path 17. The biomass fuel having a predetermined particle size or less supplied from the biomass fuel supply path 17 is supplied to the boiler 20.

The biomass grinder 10 of the present invention is a pressurized grinder, which blows pressurized air (primary air) by a primary blower 80 into the biomass grinder 10, thereby drying the crushed biomass fuel and transporting it to the furnace 21 of the boiler 20. The pressure inside the outer shell of the biomass grinder 10 becomes higher than the pressure of the outside (atmosphere).

The boiler 20 is a device that burns the biomass fuel crushed by the biomass grinder 10 through the combustion device 22, and exchanges heat between the heat generated by the combustion and the supply water or steam to generate superheated steam. The boiler 20 includes a furnace 21, a combustion device 22, a superheater 23, a reheater 24, and an economizer 25. The boiler 20 burns the biomass fuel through the combustion device 22, and exchanges heat between the combustion gas generated in the furnace 21 and the supply water or steam flowing inside the heat exchanger (superheater 23, reheater 24, economizer 25).

A combustion device 22 is provided in the middle of the furnace 21 in the height direction HD. The combustion device 22 has a plurality of burners 22a and a wind box 22b for supplying combustion air to the burners 22a. In FIG1 , although the biomass fuel supply path 17 is shown as being connected to one of the plurality of burners 22a, the biomass fuel supply path 17 may be connected to each burner 22a in a branched manner. The burner 22a above the burner 22a connected to the biomass fuel supply path 17 is connected to the second supply path 47 described later.

In FIG. 1 , 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 illustration of the pipes connected to each burner 22a is omitted. The boiler system 100 shown in FIG. 1 has a biomass grinder 10 and other grinders (omitted from the illustration) different from the grinder 41 described later. When the biomass fuel and the pulverized coal fuel are mixed, at least one of the other grinders is used to grind other solid fuels such as coal having a greater calorific value than the biomass fuel. The solid fuels grinded by the other grinders are supplied to each burner 22a.

The boiler system 100 shown in FIG1 has, in addition to the biomass grinder 10 and grinder 41, another grinder for crushing other solid fuels such as coal. Although this is to mix the biomass fuel with the pulverized coal fuel, it can also be in other forms. For example, the boiler system 100 can be equipped with one or more biomass grinders 10 and grinders 41 to become a biomass fuel-only combustion system that only burns biomass fuel.

As shown in FIG1 , a furnace bottom 21a is provided below the furnace 21 in the height direction HD. The furnace bottom 21a is immersed in a conveyor belt 43 filled with a cooling medium such as water, and the interior of the furnace 21 is isolated from the outside air. Among the biomass fuel supplied to the furnace 21, unburned biomass fuel or combustion ash that is not burned by the combustion device 22 falls to the furnace bottom 21a and is cooled by the cooling medium. As described above, the furnace bottom ash processing equipment 40 of this embodiment has a wet conveyor belt 43 that cools the unburned biomass fuel or combustion ash with a cooling medium.

The air preheater 30 is a device for heating air by exhaust gas G discharged from the furnace 21 of the boiler 20. As shown in FIG1 , the air preheater 30 is supplied with air from the blower 70 and the primary ventilator 80. In the air preheater 30, the exhaust gas G discharged from the furnace 21 is supplied through the exhaust gas supply path 26, and heat is exchanged with the air supplied from the blower 70 and the primary ventilator 80.

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

The grinder 41 is a device for crushing the bottom ash BA containing unburned biomass fuel discharged from the furnace 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 % of the total amount of biomass fuel supplied to the combustion device 22 from the biomass fuel supply path 17. Therefore, the grinder 41 is smaller than the biomass grinder 10 and requires less power.

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

The storage section 42 is a device for storing the bottom ash BA containing unburned biomass fuel transported by the conveyor belt 43. The supply amount of the bottom ash BA supplied from the storage section 42 to the grinding mill 41 is controlled by the control device 90. The conveyor belt 43 is a device for transporting the bottom ash BA containing unburned biomass fuel discharged from the furnace bottom 21a of the furnace 21 to the storage section 42.

The silo 44 is a device for temporarily storing the bottom ash BA crushed by the grinder 41. The bottom ash BA crushed by the grinder 41 is transported to the silo 44 by air supplied from the first branch supply path 51 and the second branch supply path 61. The air flowing into the silo 44 passes through the bag dust collector 44a installed in the silo 44 and is separated from the crushed bottom ash BA and discharged to the atmosphere. The control device 90 operates the blower 45, thereby supplying the bottom ash BA stored in the silo 44 to the combustion device 22 of the boiler 20 through the second supply path 47. Furthermore, since the supply amount of the bottom ash BA from the storage section 42 to the grinding mill 41 is controlled by the control device 90, it is also possible to supply the bottom ash BA to the combustion device 22 of the boiler 20 from the first supply path 46 without passing through the silo 44.

The first air supply path 50 is a flow path for supplying heated air supplied from the primary ventilator 80 and heated by the air preheater 30 to the biomass grinder 10. An opening and closing damper 50a and an adjusting damper 50b are provided in the first air supply path 50. The opening and closing damper 50a is opened by the control device 90, and the opening degree of the adjusting damper 50b is adjusted, thereby adjusting the flow rate of the heated air guided to the biomass grinder 10 through the first air supply path 50.

The first branch supply path 51 is a flow path for supplying a part of the heated air to the grinder 41 by branching from the first air supply path 50. The first branch supply path 51 supplies a part of the heated air to the grinder 41 by branching from the first air supply path 50, thereby drying the unburned biomass fuel crushed by the grinder 41. The first branch supply path 51 is provided with an opening and closing damper 51a and an adjusting damper 51b. The control device 90 opens the opening and closing damper 51a and adjusts the opening of the adjusting damper 51b, thereby adjusting the flow rate of the heated air guided to the grinder 41 through the first branch supply path 51.

The second air supply path 60 is a flow path for supplying non-heated air (cold air) supplied from the primary ventilator 80 and not heated by the air preheater 30 to the biomass grinder 10. An opening and closing damper 60a and an adjusting damper 60b are provided in the second air supply path 60. The opening and closing damper 60a is opened by the control device 90, and the opening degree of the adjusting damper 60b is adjusted, thereby adjusting the flow rate of the cold air guided to the biomass grinder 10 through the second air supply path 60.

The second branch supply path 61 is a flow path for supplying a part of the cold air to the grinder 41 by branching from the second air supply path 60. An opening and closing damper 61a and an adjusting damper 61b are provided in the second branch supply path 61. The opening and closing damper 61a is opened by the control device 90, and the opening degree of the adjusting damper 61b is adjusted, thereby adjusting the flow rate of the cold air guided to the grinder 41 through the second branch supply path 61.

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

The primary ventilator 80 is a device that blows air (outside air) into the first air supply path 50 and the second air supply path 60 to supply the air to the biomass grinder 10 . In addition, the primary ventilator 80 also blows air (outside air) into the first branch supply path 51 and the second branch supply path 61 to supply the air to the grinder 41 .

The control device 90 is a device for controlling each part of the boiler system 100. The control device 90 reads a control program from a memory unit (not shown) and executes the control program to control each part of the boiler system 100.

Next, referring to FIG. 2 , the startup operation of the bottom ash treatment device 40 will be described. FIG. 2 is a flow chart showing the startup operation of the bottom ash treatment device 40 of the first embodiment. Each process shown in FIG. 2 is executed by the control device 90. In addition, when executing the process shown in FIG. 2 , each part of the boiler system 100 including the biomass grinder 10 and the boiler 20 except the bottom ash treatment device 40 is considered to have been started in advance.

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

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

In step S103, the control device 90 opens the on-off damper 61a and adjusts the opening of the adjustment damper 61b to open the second branch supply path 61. The opening of the adjustment damper 61b is adjusted in accordance with the target temperature inside the grinder 41 or the required air volume.

In step S104, the control device 90 opens the on-off damper 51a and adjusts the opening of the adjustment damper 51b to open the first branch supply path 51. The opening of the adjustment damper 51b is adjusted in accordance with the target temperature inside the grinder 41 or the required air volume.

In step S105, the control device 90 determines whether the interior of the grinder 41 has reached a specified temperature. If YES, the process proceeds to step S106, and if NO, the determination of step S105 is repeated.

In step S106, the control device 90 starts supplying the bottom ash BA from the storage unit 42 to the grinding mill 41, thereby starting the grinding operation of the bottom ash BA by the grinding mill 41. The bottom ash BA ground by the grinding mill 41 is supplied to the silo 44 through 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 added. If it is YES, the process proceeds to step S108, and if it is NO, the determination of step S107 is repeatedly executed. In step S108, the control device 90 operates the blower 45 to start supplying bottom ash BA to the boiler 20. As described above, the control device 90 starts the bottom ash processing equipment 40.

Next, the stopping operation of the bottom ash treatment equipment 40 will be described with reference to Fig. 3. Fig. 3 is a flow chart showing the stopping operation of the bottom ash treatment 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 conveyor belt 43 from supplying the bottom ash BA to the storage section 42, and switches the discharge direction to discharge the bottom ash BA to the outside different from the storage section 42. In addition, if there is no mechanism for discharging the bottom ash BA to the outside, the processing of steps S202 and S203 can be omitted, and the processing can be advanced to step S204 during the stop process of the boiler 20.

In step S203, the control device 90 determines whether the storage amount of the bottom ash BA stored in the storage section 42 is lower than a predetermined specified amount. If it is YES, the process proceeds to step S204. If it is NO, the determination of step S203 is repeatedly executed.

In step S204, the control device 90 controls the amount of bottom ash BA supplied from the storage section 42 to the grinding mill 41 to be reduced to a predetermined minimum amount, that is, a specified amount.

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

In step S206, the control device 90 determines whether the temperature inside the grinding mill 41 has fallen below the specified temperature. If YES, the process proceeds to step S207, and if NO, the determination of step S206 is repeated.

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

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

The functions and effects of the boiler system 100 of the present embodiment described above are described. According to the boiler system 100 of the present embodiment, the biomass fuel crushed by the biomass grinder 10 is burned in the combustion device 22, and steam is generated in the boiler 20. The air is heated in the air preheater 30 by the exhaust gas G discharged from the boiler 20, and the heated air is supplied to the biomass grinder 10 through the first air supply path 50. The unburned biomass fuel discharged from the boiler 20 is supplied to the combustion device 22 again after being dried by the heated air supplied from the first branch supply path 51 through the furnace bottom ash processing equipment 40.

According to the boiler system 100 of the present embodiment, when the biomass is pulverized by the biomass grinder 10, even if the temperature of the heated air (primary air) supplied to the biomass grinder 10 is set lower than that of the case of pulverizing pulverized coal fuel in consideration of the ignition property of the biomass fuel, it is not necessary to significantly reduce the amount of heat recovered from the exhaust gas G by the air preheater 30. This is because a part of the heated air is used to dry the unburned biomass fuel in the grinder 41. Therefore, according to the boiler system 100 of the present embodiment, the boiler efficiency can be improved when the biomass fuel is burned by the combustion device 22 and steam is generated in the boiler 20.

Furthermore, according to the boiler system 100 of the present embodiment, the unburned biomass fuel discharged from the boiler 20 is transported to the grinder 41 through the conveyor belt 43 and the storage unit 42, and is crushed by the grinder 41. According to the boiler system 100 of the present embodiment, the unburned biomass fuel crushed by the grinder 41 is dried by the heated air supplied from the first branch supply path 51, thereby improving the boiler efficiency when the combustion device 22 burns the biomass fuel and generates steam in the boiler 20.

Furthermore, according to the boiler system 100 of the present embodiment, the non-heated air supplied from the second air supply path 60 to the biomass grinder 10 is mixed with the heated air supplied from the first air supply path 50 to the biomass grinder 10, so that the temperature of the mixed air (primary air) of the non-heated air and the heated air guided to the inside of the biomass grinder 10 is appropriately adjusted. Furthermore, the non-heated air supplied from the second branch supply path 61 to the grinder 41 is mixed with the heated air supplied from the first branch supply path 51 to the grinder 41, so that the temperature of the mixed air (primary air) of the non-heated air and the heated air guided to the inside of the grinder 41 is appropriately adjusted.

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 belt 43 filled with the cooling medium and can be cooled by the cooling medium. The unburned biomass fuel contains the cooling medium due to contact with the cooling medium on the conveyor belt 43, but is dried by the heated air supplied from the first branch supply path 51 in the bottom ash treatment equipment 40. Therefore, in the boiler 20 having the wet conveyor belt 43, the heat of the exhaust gas discharged from the boiler 20 can be effectively recovered by the air preheater 30 to dry the unburned biomass fuel.

Furthermore, according to the boiler system 100 of the present embodiment, the biomass fuel crushed by the biomass grinder 10 is burned in the combustion device 22, and steam is generated in the boiler 20. The unburned biomass fuel discharged from the boiler 20 is transported to the grinder 41 through the conveyor belt 43 and the storage unit 42, and is crushed by the grinder 41. The unburned biomass fuel crushed by the grinder 41 is supplied to the combustion device 22 again through the bottom ash processing equipment 40. According to the boiler system 100 of the present embodiment, the unburned biomass fuel discharged from the boiler 20 is crushed by the grinder 41 and then supplied to the combustion device 22 again, so that the unburned biomass fuel can be reliably burned in the combustion device 22.

According to the boiler system 100 of the present embodiment, the unburned biomass fuel crushed by the grinder 41 is directly supplied to the combustion device 22, so that the existing supply path for supplying the biomass fuel from the biomass grinder 10 to the combustion device 22 is not affected.

[Second embodiment] Next, the boiler system 100A of the second embodiment of the present invention is described. This embodiment is a variation of the first embodiment, and except for the cases specifically described below, it is considered to be the same as the first embodiment, and the description thereof will be omitted below.

In the boiler system 100 of the first embodiment, the second supply path 47 of the bottom ash processing equipment 40 directly supplies the unburned biomass fuel crushed by the grinder 41 to the combustion device 22, or the first supply path 46 directly supplies the unburned biomass fuel crushed by the grinder 41 to the combustion device 22. In contrast, in the boiler system 100A of the present embodiment, the first supply path 46 of the bottom ash processing equipment 40A guides the unburned biomass fuel crushed by the grinder 41 to the feeding part 110 for feeding the additive into the combustion device 22. The additive is added to the furnace 21 of the boiler 20 to reduce ash adhesion or corrosion to the furnace 21 or the heat transfer part of the boiler 20 when using biomass fuel. For example, coal ash is used.

Fig. 4 is a diagram showing a schematic structure of a boiler system 100A according to a second embodiment of the present invention. As shown in Fig. 4, the boiler system 100A includes an input unit 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 the blower 45 of the boiler system 100 according to the first embodiment.

The input part 110 is a device for inputting an additive (e.g., coal ash) into the combustion device 22. The control device 90 operates the blower (additive input device) 120, thereby supplying the additive stored in the input part 110 to the combustion device 22 through the additive supply path 130. As shown in FIG. 4, in this embodiment, the additive supply path 130 is configured to merge with the biomass fuel supply path 17. The additive merged from the additive supply path 130 to 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 grinder 10.

According to the boiler system 100 of this embodiment, by adding additives, ash adhesion or corrosion to the furnace 21 or the heat transfer part of the boiler 20 when using biomass fuel can be reduced. In addition, the unburned biomass fuel crushed by the grinder 41 can be appropriately supplied to the combustion device 22 through the input part 110.

In this embodiment, the supply path to the combustion device 22 for the unburned biomass fuel crushed by the grinder 41 can be shared with the additive supply path 130, so it will not affect the piping arrangement in the existing boiler equipment, and can be easily modified and added. In addition, the unburned biomass fuel can be burned in the burner 22a connected to the biomass fuel supply path 17, so an independent combustion device for burning the unburned biomass fuel is not required.

[Third embodiment] Next, the boiler system 100B of the third embodiment of the present invention is described. This embodiment is a variation of the first embodiment, and except for the cases specifically described below, it is considered to be the same as the first embodiment, and the description thereof will be omitted below.

In the boiler system 100 of the first embodiment, the second supply path 47 of the bottom ash processing equipment 40 supplies the unburned biomass fuel crushed by the grinder 41 to the burner 22a different from the burner 22a supplied with the biomass fuel from the biomass fuel supply path 17. In contrast, in the boiler system 100B of the present embodiment, the second supply path 47 of the bottom ash processing equipment 40B allows the unburned biomass fuel crushed by the grinder 41 to merge with the biomass fuel supply path 17. Furthermore, similarly to the first embodiment, the amount of bottom ash BA supplied from the storage section 42 to the grinder 41 is controlled by the control device 90, so that the unburned biomass fuel crushed by the grinder 41 can be merged into the biomass fuel supply path 17 from the first supply path 46 without passing through the silo 44.

FIG5 is a diagram showing a schematic structure of a boiler system 100B according to a third embodiment of the present invention. As shown in FIG5, in the boiler system 100B according to the present embodiment, the second supply path 47 of the bottom ash processing device 40B is arranged so that the unburned biomass fuel crushed by the grinder 41 merges with the biomass fuel supply path 17. The control device 90 operates the blower 45, thereby causing the bottom ash BA containing the unburned biomass fuel stored in the silo 44 to merge with the biomass fuel supply path 17 from the second supply path 47. Furthermore, the control device 90 controls the supply amount from the storage unit 42 to the grinder 41 , thereby allowing the bottom ash BA containing unburned biomass fuel that has been crushed by the grinder 41 to merge into the biomass fuel supply path 17 from the first supply path 46 .

According to the boiler system 100B of this embodiment, the unburned biomass fuel crushed by the grinder 41 is merged into the existing biomass fuel supply path 17 for supplying the biomass fuel from the biomass grinder 10 to the combustion device 22. Therefore, it is not necessary to add a burner 22a for burning the unburned biomass fuel to the combustion device 22 as in the boiler system 100 of the first embodiment, and the existing equipment can be easily modified or added.

[Fourth embodiment] Next, the boiler system 100C of the fourth embodiment of the present invention will be described. This embodiment is a variation of the first embodiment, and except for the cases specifically described below, it is considered to be the same as the first embodiment, and the description thereof will be omitted below.

In the boiler system 100 of the first embodiment, the second supply path 47 of the bottom ash processing device 40 directly supplies the unburned biomass fuel crushed by the grinder 41 to the combustion device 22, or the first supply path 46 directly supplies the unburned biomass fuel crushed by the grinder 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 device 40C guides the unburned biomass fuel crushed by the grinder 41 to the biomass fuel storage unit 15.

FIG6 is a diagram showing a schematic structure of a boiler system 100C according to a fourth embodiment of the present invention. As shown in FIG6 , the boiler system 100C is configured such that the first supply path 46 of the bottom ash processing device 40C guides the unburned biomass fuel crushed by the grinder 41 to the biomass fuel storage 15. The control device 90 operates the blower 45 to guide the bottom ash BA containing the unburned biomass fuel stored in the silo 44 from the first supply path 46 to the biomass fuel storage 15.

According to the boiler system 100C of this embodiment, the unburned biomass fuel crushed by the grinder 41 is guided to the biomass fuel storage section 15 for storing the biomass fuel crushed by the biomass grinder 10, so the control operation of the existing fuel supply system including the biomass fuel supply path 17 can be maintained without change.

[Fifth Implementation] Next, the boiler system 100D of the fifth implementation of the present invention will be described. This implementation is a variation of the first implementation, and except for the cases specifically described below, it is considered to be the same as the first implementation, and the description thereof will be omitted below.

In the boiler system 100 of the first embodiment, the second supply path 47 of the bottom ash processing equipment 40 directly supplies the unburned biomass fuel crushed by the grinder 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 guides the unburned biomass fuel crushed by the grinder 41 to the biomass fuel conveyor (biomass fuel transport unit) 18 for transporting the biomass fuel to the biomass fuel storage unit 15.

FIG7 is a diagram showing a schematic structure of a boiler system 100D according to the fifth embodiment of the present invention. As shown in FIG7 , the boiler system 100D has a biomass fuel conveyor belt 18 for conveying the biomass fuel to the biomass fuel storage unit 15. The boiler system 100D is configured such that the second supply path 47 of the bottom ash processing device 40D guides the unburned biomass fuel crushed by the grinder 41 to the biomass fuel conveyor belt 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 belt 18. The bottom ash BA guided to the biomass fuel conveyor belt 18 is stored in the biomass fuel storage unit 15 together with the biomass fuel.

According to the boiler system 100D of this embodiment, the unburned biomass fuel crushed by the grinder 41 is guided to the biomass fuel conveyor belt 18, which is transported to the biomass fuel storage section 15 for storing the biomass fuel crushed by the biomass grinder 10, so 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 grasped as follows, for example. The first aspect of the present invention is a biomass pulverizing system (100), comprising: a first pulverizing device (10) for pulverizing biomass fuel; a boiler (20) for burning the biomass fuel pulverized by the first pulverizing device in a combustion device to generate steam; an air preheater (30) for heating air by exhaust gas discharged from the boiler; a first air supply path (50) for supplying heated air heated by the air preheater to the first pulverizing device; a first branch supply path (51) for branching a part of the heated air from the first air supply path; and a resupply unit (40) for drying the unburned biomass fuel discharged from the boiler by the heated air supplied from the first branch supply path and supplying the dried biomass fuel to the combustion device again.

According to the first aspect of the biomass pulverizing system of the present invention, the biomass fuel pulverized by the first pulverizing device is burned in the combustion device to generate steam in the boiler. The exhaust gas discharged from the boiler is used to heat the air in the air preheater, and the heated air is supplied to the first pulverizing device through the first air supply path. The unburned biomass fuel discharged from the boiler is dried by the heated air supplied from the first branch supply path through the resupply unit and then supplied to the combustion device again.

According to the biomass pulverizing system of the first aspect of the present invention, even if the temperature of the heated air (primary air) supplied to the first pulverizing device is set lower than that of the pulverized coal fuel in consideration of the ignition properties of the biomass fuel, the reduction in the amount of heat recovered from the exhaust gas of the air preheater can be suppressed. This is because a part of the heated air is used to dry the unburned biomass fuel, so it is possible to suppress the situation where the inside of the first pulverizing device becomes excessively hot due to the heated air supplied to the first pulverizing device. Therefore, according to the biomass pulverizing system of the first aspect of the present invention, the boiler efficiency can be improved when the combustion device burns the biomass fuel and steam is generated in the boiler.

The second aspect of the biomass pulverizing system of the present invention is a system according to the first aspect, further comprising the following structure: that is, the resupply section comprises: a second pulverizing device (41) for pulverizing the unburned biomass fuel discharged from the boiler; and an unburned fuel transport section (43) for transporting the unburned biomass fuel discharged from the boiler to the second pulverizing device, and the first branch supply path for branching a part of the heated air from the first air supply path and supplying the heated air to the second pulverizing device to dry the unburned biomass fuel pulverized by the second pulverizing device.

According to the second aspect of the biomass pulverizing system of the present invention, the unburned biomass fuel discharged from the boiler is transported to the second pulverizing device by the unburned fuel transport unit and pulverized by the second pulverizing device. According to the second aspect of the biomass pulverizing system of the present invention, the unburned biomass fuel pulverized by the second pulverizing device is dried by the heated air supplied from the first branch supply path, thereby improving the boiler efficiency when the combustion device burns the biomass fuel and generates steam in the boiler.

The biomass pulverizing system of the third aspect of the present invention is the biomass pulverizing system of the second aspect, further comprising the following structure: a second air supply path (60) for supplying non-heated air that has not been heated by the air preheater to the first pulverizing device; and a second branch supply path (61) for branching a part of the non-heated air from the second air supply path and supplying the air to the second pulverizing device.

According to the biomass pulverizing system of the third aspect of the present invention, the non-heated air supplied from the second air supply path to the first pulverizing device is mixed with the heated air supplied from the first air supply path to the first pulverizing device, so that the temperature of the mixed air (primary air) of the non-heated air and the heated air guided to the inside of the first pulverizing device is appropriately adjusted. Furthermore, the non-heated air supplied from the second branch supply path to the second pulverizing device is mixed with the heated air supplied from the first branch supply path to the second pulverizing device, so that the temperature of the mixed air (primary air) of the non-heated air and the heated air guided to the inside of the second pulverizing device is appropriately adjusted.

The fourth aspect of the biomass pulverizing system of the present invention is any one of the first to third aspects, and further has the following structure: That is, the boiler has a wet unburned fuel transporting section (43) for cooling the combustion ash of the biomass fuel with a cooling medium.

According to the biomass pulverizing system of the fourth aspect of the present invention, the combustion ash generated by the biomass fuel burned in the boiler can be cooled by the coolant in the wet unburned fuel transport section. The unburned biomass fuel contains the coolant because it contacts the coolant in the unburned fuel transport section, but is dried by the heated air supplied from the first branch supply path in the resupply section. Therefore, in the boiler having the wet unburned fuel transport section, the heat of the exhaust gas discharged from the boiler can be effectively recovered by the air preheater to dry the unburned biomass fuel.

The fifth aspect of the biomass pulverizing system of the present invention comprises: a first pulverizing device for pulverizing biomass fuel; a boiler for burning the aforementioned biomass fuel pulverized by the aforementioned first pulverizing device in a combustion device to generate steam; a second pulverizing device for pulverizing the aforementioned unburned biomass fuel discharged from the aforementioned boiler; a transport section for transporting the aforementioned unburned biomass fuel discharged from the aforementioned boiler to the aforementioned second pulverizing device; and a resupply section for resupplying the aforementioned unburned biomass fuel pulverized by the aforementioned second pulverizing device to the aforementioned combustion device.

According to the fifth aspect of the biomass pulverizing system of the present invention, the biomass fuel pulverized by the first pulverizing device is burned in the combustion device, and steam is generated in the boiler. The unburned biomass fuel discharged from the boiler is transported to the second pulverizing device by the unburned fuel transport unit and pulverized by the second pulverizing device. The unburned biomass fuel pulverized by the second pulverizing device is re-supplied to the combustion device by the re-supply unit. According to the fifth aspect of the biomass pulverizing system of the present invention, the unburned biomass fuel discharged from the boiler is re-supplied to the combustion device after being pulverized by the second pulverizing device, thereby enabling the unburned biomass fuel to be reliably burned in the combustion device.

The sixth aspect of the biomass pulverizing system of the present invention is, in any one of the second aspect, the third aspect or the fifth aspect, further provided with the following structure: That is, the resupply section has an unburned fuel supply path (47) for supplying the unburned biomass fuel pulverized by the second pulverizing device to the combustion device.

According to the sixth aspect of the biomass pulverizing system of the present invention, the unburned biomass fuel pulverized by the second pulverizing device is directly supplied to the combustion device, so there is no impact on the existing supply path for supplying the biomass fuel from the first pulverizing device to the combustion device.

The seventh aspect of the biomass pulverizing system of the present invention is any one of the second aspect, the third aspect or the fifth aspect, and further has the following structure: that is, it has a feeding part (110) for feeding the additive into the combustion device, and the resupply part guides the unburned biomass fuel pulverized by the second pulverizing device to the feeding part.

According to the biomass pulverizing system of the seventh aspect of the present invention, the attachment of combustion ash caused by the combustion of biomass fuel to the furnace of the boiler can be appropriately reduced by adding an additive. In addition, the unburned biomass fuel pulverized by the second pulverizing device can be appropriately supplied to the combustion device through the input part. In this form, the supply path to the combustion device 22 dedicated to the unburned biomass fuel pulverized by the grinder 41 can be shared with the additive supply path 130, so it will not affect the piping configuration in the existing boiler equipment, and can be easily modified and added. In addition, the unburned biomass fuel can be burned in the burner 22a connected to the biomass fuel supply path 17, so an independent combustion device for burning the unburned biomass fuel is not required.

The biomass pulverizing system of the eighth aspect of the present invention is any one of the second aspect, the third aspect or the fifth aspect, and further has the following structure: that is, it has a biomass fuel supply path (17) for supplying the aforementioned biomass fuel pulverized by the aforementioned first pulverizing device to the aforementioned combustion device, and the aforementioned resupply section allows the aforementioned unburned biomass fuel pulverized by the aforementioned second pulverizing device to merge with the aforementioned biomass fuel supply path.

According to the 8th aspect of the biomass pulverizing system of the present invention, the unburned biomass fuel pulverized by the second pulverizing device is merged into the existing fuel supply path for supplying the biomass fuel from the first pulverizing device to the combustion device. Therefore, there is no need to add a burner for burning the unburned biomass fuel to the combustion device, and the existing equipment can be easily modified or added.

The ninth aspect of the present invention is a biomass pulverizing system in any one of the second aspect, the third aspect or the fifth aspect, further comprising the following structure: that is, a biomass fuel storage section (15) for storing the biomass fuel pulverized by the first pulverizing device, and the resupply section for guiding the unburned biomass fuel pulverized by the second pulverizing device to the biomass fuel storage section.

According to the ninth aspect of the biomass pulverizing system of the present invention, the unburned biomass fuel pulverized by the second pulverizing device is guided to the biomass fuel storage section for storing the biomass fuel pulverized by the first pulverizing device, so the control operation of the existing fuel supply system can be maintained without change.

The tenth aspect of the biomass pulverizing system of the present invention is, in the second aspect, the third aspect or the fifth aspect, further provided with the following structure: that is, provided with: a biomass fuel storage section (42) for storing the biomass fuel pulverized by the first pulverizing device; and a biomass fuel transport section (43) for transporting the biomass fuel to the biomass fuel storage section, and the resupply section for guiding the unburned biomass fuel pulverized by the second pulverizing device to the biomass fuel transport section.

According to the biomass pulverizing system of the tenth aspect of the present invention, the unburned biomass fuel pulverized by the second pulverizing device is guided to the biomass fuel transporting section, and the biomass fuel transporting section is used to transport the biomass fuel to the biomass fuel storage section for storing the biomass fuel, so the control operation of the existing fuel supply system can be maintained without change.

The operating method of the biomass pulverizing system of the 11th aspect of the present invention comprises: a first pulverizing device for pulverizing biomass fuel; a boiler for burning the biomass fuel pulverized by the first pulverizing device in a combustion device to generate steam; an air preheater for heating air by exhaust gas discharged from the boiler; a first air supply path for supplying the heated air heated by the air preheater to the first pulverizing device; device; and a first branch supply path, which branches off a part of the heated air from the first air supply path, the operation method of the biomass pulverizing system comprises: a drying process, which dries the unburned biomass fuel discharged from the boiler by supplying the heated air from the first branch supply path; and a resupply process, which resupplies the unburned biomass fuel dried by the drying process to the combustion device.

According to the operation method of the biomass pulverizing system of the eleventh aspect of the present invention, the biomass fuel pulverized by the first pulverizing device is burned in the combustion device to generate steam in the boiler. The exhaust gas discharged from the boiler is used to heat the air in the air preheater, and the heated air is supplied to the first pulverizing device through the first air supply path. The unburned biomass fuel discharged from the boiler is dried by the heated air supplied from the first branch supply path through the drying process, and is supplied to the combustion device again through the resupply process.

According to the operating method of the biomass pulverizing system of the 11th aspect of the present invention, even if the temperature of the heated air (primary air) supplied to the first pulverizing device is set to be lower than that of the pulverized coal fuel in consideration of the ignition properties of the biomass fuel, it is not necessary to significantly reduce the heat recovery amount of the exhaust gas from the air preheater. This is because a part of the heated air is used to dry the unburned biomass fuel, so it is possible to suppress the situation where the first pulverizing device becomes overly hot due to the heated air supplied to the first pulverizing device. Therefore, according to the operating method of the biomass pulverizing system of the 1st aspect of the present invention, the boiler efficiency can be improved when the combustion device burns the biomass fuel and steam is generated in the boiler.

The operating method of the biomass pulverizing system of the twelfth aspect of the present invention comprises: a first pulverizing device for pulverizing biomass fuel; a boiler for burning the aforementioned biomass fuel pulverized by the aforementioned first pulverizing device in a combustion device to generate steam; and a second pulverizing device for pulverizing the aforementioned unburned biomass fuel discharged from the aforementioned boiler. The operating method of the biomass pulverizing system comprises: a transporting process for transporting the aforementioned unburned biomass fuel discharged from the aforementioned boiler to the aforementioned second pulverizing device; and a resupply process for resupplying the aforementioned unburned biomass fuel pulverized by the aforementioned second pulverizing device to the aforementioned combustion device.

According to the operating method of the biomass pulverizing system of the 12th aspect of the present invention, the biomass fuel pulverized by the first pulverizing device is burned in the combustion device, and steam is generated in the boiler. The unburned biomass fuel discharged from the boiler is transported to the second pulverizing device through a transport process and pulverized by the second pulverizing device. The unburned biomass fuel pulverized by the second pulverizing device is re-supplied to the combustion device through a re-supply process. According to the operating method of the biomass pulverizing system of the 11th aspect of the present invention, the unburned biomass fuel discharged from the boiler is re-supplied to the combustion device after being pulverized by the second pulverizing device, thereby ensuring that the unburned biomass fuel can be reliably burned in the combustion device.

10: Biomass grinder (first crushing device) 15: Biomass fuel storage 17: Biomass fuel supply line 18: Biomass fuel conveyor belt 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: Furnace bottom ash treatment equipment 41: Grinder 42: Storage 43: Conveyor belt 44: Silo 45: Blower 46: First supply line 47: Second supply line 50: First air supply line 50a,51a,60a,61a: Open/Close damper 50b,51b,60b,61b: Adjust damper 51: First branch supply path 60: Second air supply path 61: Second branch supply path 70: Blowing fan 71: Combustion air supply path 80: Primary ventilator 90: Control device 100,100A,100B,100C,100D: Boiler system 110: Input section 120: Blower 130: Additive supply path BA: Bottom ash G: Exhaust HD: Height direction

[Figure 1] is a diagram showing a schematic structure of a boiler system of the first embodiment of the present invention. [Figure 2] is a flow chart showing the start-up action of the bottom ash treatment equipment of the first embodiment. [Figure 3] is a flow chart showing the stop action of the bottom ash treatment equipment of the first embodiment. [Figure 4] is a diagram showing a schematic structure of a boiler system of the second embodiment of the present invention. [Figure 5] is a diagram showing a schematic structure of a boiler system of the third embodiment of the present invention. [Figure 6] is a diagram showing a schematic structure of a boiler system of the fourth embodiment of the present invention. [Figure 7] is a diagram showing a schematic structure of a boiler system of the fifth embodiment of the present invention.

10: Biomass grinder (first crushing device)

15: Biomass fuel storage department

17: Biomass fuel supply route

20: Boiler

21: Fireplace

21a: Furnace bottom

22: Combustion device

22a: Burner

22b: Bellows

23:Superheater

24: Reheater

25: Economizer

26: Exhaust supply line

30: Air preheater

40: Bottom ash treatment equipment

41: Grinder

42: Storage Department

43:Conveyor belt

44: Tongcang

44a:Bag dust collector

45: Blower

46: Supply route 1

47: Second supply route

50: 1st air supply route

50a,51a,60a,61a: Open and close damper

50b,51b,60b,61b: Adjust the damper

51: The first branch supply route

60: Second air supply route

61: Second branch supply route

70: Blow into the ventilator

71: Combustion air supply line

80: Primary ventilator

90: Control device

100: Boiler system

BA: Bottom ash

G: Exhaust

HD: height direction

Claims (12)

A biomass pulverizing system comprises: a first pulverizing device for pulverizing biomass fuel; a boiler for burning the aforementioned biomass fuel pulverized by the aforementioned first pulverizing device in a combustion device to generate steam; an air preheater for heating air by exhaust gas discharged from the aforementioned boiler; a first air supply path for supplying heated air heated by the aforementioned air preheater to the aforementioned first pulverizing device; a first branch supply path for branching a part of the aforementioned heated air from the aforementioned first air supply path; and a resupply section for drying the aforementioned unburned aforementioned biomass fuel discharged from the aforementioned boiler by the aforementioned heated air supplied from the aforementioned first branch supply path and supplying it to the aforementioned combustion device again. The biomass pulverizing system as described in claim 1, wherein, the resupply section comprises: a second pulverizing device for pulverizing the unburned biomass fuel discharged from the boiler; and an unburned fuel transport section for transporting the unburned biomass fuel discharged from the boiler to the second pulverizing device, the first branch supply path for branching a part of the heated air from the first air supply path and supplying it to the second pulverizing device to dry the unburned biomass fuel pulverized by the second pulverizing device. The biomass pulverizing system as described in claim 2 comprises: a second air supply path, which supplies non-heated air that has not been heated by the air preheater to the first pulverizing device; and a second branch supply path, which branches a part of the non-heated air from the second air supply path and supplies it to the second pulverizing device. The biomass pulverizing system as described in any one of claims 1 to 3, wherein the boiler has a wet unburned fuel transporting section for cooling the combustion ash of the biomass fuel with a cooling medium. A biomass pulverizing system comprises: a first pulverizing device for pulverizing biomass fuel; a boiler for burning the biomass fuel pulverized by the first pulverizing device in a combustion device to generate steam; a second pulverizing device for pulverizing the unburned biomass fuel discharged from the boiler; an unburned fuel transport unit for transporting the unburned biomass fuel discharged from the boiler to the second pulverizing device; and a resupply unit for resupplying the unburned biomass fuel pulverized by the second pulverizing device to the combustion device. A biomass pulverizing system as described in any one of claim 2, claim 3 or claim 5, wherein the resupply section has an unburned fuel supply path, which supplies the unburned biomass fuel pulverized by the second pulverizing device to the combustion device. A biomass pulverizing system as described in any one of claim 2, claim 3 or claim 5, wherein, it has a feeding section for feeding the additive into the aforementioned combustion device, and the aforementioned resupply section guides the aforementioned unburned aforementioned biomass fuel pulverized by the aforementioned second pulverizing device to the aforementioned feeding section. A biomass pulverizing system as described in any one of claim 2, claim 3 or claim 5, wherein: It has a biomass fuel supply path for supplying the aforementioned biomass fuel pulverized by the aforementioned first pulverizing device to the aforementioned combustion device, The aforementioned resupply section allows the aforementioned unburned biomass fuel pulverized by the aforementioned second pulverizing device to merge with the aforementioned biomass fuel supply path. A biomass pulverizing system as described in any one of claim 2, claim 3 or claim 5, wherein, a biomass fuel storage section is provided for storing the aforementioned biomass fuel pulverized by the aforementioned first pulverizing device, and the aforementioned resupply section guides the aforementioned unburned aforementioned biomass fuel pulverized by the aforementioned second pulverizing device to the aforementioned biomass fuel storage section. The biomass pulverizing system as described in any one of claim 2, claim 3 or claim 5, wherein the system comprises: a biomass fuel storage section, which stores the aforementioned biomass fuel pulverized by the aforementioned first pulverizing device; and a biomass fuel transport section, which transports the aforementioned biomass fuel to the aforementioned biomass fuel storage section, and the aforementioned resupply section, which guides the aforementioned unburned biomass fuel pulverized by the aforementioned second pulverizing device to the aforementioned biomass fuel transport section. A method for operating a biomass pulverizing system, the biomass pulverizing system comprising: a first pulverizing device for pulverizing biomass fuel; a boiler for burning the aforementioned biomass fuel pulverized by the aforementioned first pulverizing device in a combustion device to generate steam; an air preheater for heating air by exhaust gas discharged from the aforementioned boiler; a first air supply path for supplying heated air heated by the aforementioned air preheater to the aforementioned first pulverizing device; and a first branch supply path for branching a portion of the aforementioned heated air from the aforementioned first air supply path. The method for operating the biomass pulverizing system comprises: a drying process for drying the aforementioned unburned biomass fuel discharged from the aforementioned boiler by supplying the aforementioned heated air from the aforementioned first branch supply path; and The resupply process is to resupply the unburned biomass fuel dried in the drying process to the combustion device. A method for operating a biomass pulverizing system, the biomass pulverizing system comprising: a first pulverizing device for pulverizing biomass fuel; a boiler for burning the biomass fuel pulverized by the first pulverizing device in a combustion device to generate steam; and a second pulverizing device for pulverizing the unburned biomass fuel discharged from the boiler. The method for operating the biomass pulverizing system comprises: a transport process for transporting the unburned biomass fuel discharged from the boiler to the second pulverizing device; and a resupply process for resupplying the unburned biomass fuel pulverized by the second pulverizing device to the combustion device.

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