JP6730661B2 - Method for producing finely divided biomass, apparatus for producing finely divided biomass, and boiler apparatus - Google Patents

Description

The present invention relates to a method for producing pulverized biomass, an apparatus for producing pulverized biomass, and a boiler device.

Patent Document 1 discloses a biomass crushing device and a biomass-coal co-firing system that pulverize wood-based biomass in stages by a plurality of mills to pulverize it and supply it to a pulverized coal cooking boiler as fuel.
Further, in Patent Document 2, organic waste is stored in a container, and after the waste is heated (steamed) by high-temperature and high-pressure steam, the pressure inside the container is momentarily released to adiabatically expand water. There is disclosed a steam explosion (steam explosion) type waste treatment device that pulverizes (exploses) a solid component by energy.

JP 2012-83017 A JP, 2010-37536, A

Like the apparatus and system described in Patent Document 1, biomass, which is a solid material, is pulverized by a mechanical pulverizer (mill) such as a hammer mill, a roller mill, and a cutter mill, and is supplied as fuel to, for example, a pulverized coal cooking boiler. There is something to do. For this purpose, the average particle size of biomass must be pulverized to about 0.5-1.0 mm.

However, in general, when a large amount of biomass is pulverized by a mill, the minimum size is only about 2.0 mm, and in order to further pulverize the biomass, it is pulverized stepwise by a plurality of mills as in Patent Document 1, etc. However, there is a problem that energy consumption such as electric power for operating the mill increases.

In particular, when the raw material biomass is a so-called wet biomass that contains a large amount of water (for example, 50 wt %), conventionally, dried dry biomass is pulverized to a biomass water content of about 10 wt% or less to generate a biomass fuel. doing. In this case, since the pretreatment of drying the biomass is required, the amount of energy consumption such as electric power for operating the dryer is increased and the pretreatment facility called the dryer is required.

Therefore, as in the waste treatment device described in Patent Document 2, in order to reduce the energy consumption required for pulverizing biomass, the steam generated in large quantities in the boiler is effectively utilized and the biomass is crushed by steam explosion. It is possible.
However, in this steam explosion, since steam is mixed with biomass and steamed, a large amount of condensed water is generated after steam explosion. Since this condensed water contains impurities, it cannot be reused as water for steam generation in the boiler, and must be discharged to the outside of the system through a discharge facility after performing neutralization treatment, separation treatment, etc. .. Therefore, the device of Patent Document 2 has a problem that a post-treatment facility after steam explosion is separately required, and facility cost and energy consumption for operating the facility are increased.

The present invention has been made in view of such problems, and an object thereof is a method for producing pulverized biomass capable of forming pulverized biomass as a fuel by pulverizing the biomass with less energy. The present invention provides a manufacturing apparatus for pulverized biomass, and a boiler apparatus that can reduce the operating cost of a boiler, reduce facility cost, and improve combustion efficiency by using the pulverized biomass.

In order to achieve the above-mentioned object, the method for producing pulverized biomass of the present invention includes a crushing step in which biomass is hermetically sealed and heated, and steam-exploded to generate pulverized biomass with moisture contained in the biomass, and pulverized biomass. And a water content adjusting step of adjusting the water content of .
Further, the apparatus for producing pulverized biomass of the present invention is equipped with a crusher that hermetically seals and heats the biomass, and steam-blasts the biomass with the water content of the biomass to generate pulverized biomass. And a container, a heating source that indirectly heats the biomass by heating the container, and a water content adjusting unit that adjusts the water content of the pulverized biomass .

Further, the boiler apparatus of the present invention is a boiler that hermetically heats and heats biomass, and explodes the steam with the moisture content of the biomass to generate finely divided biomass, and a boiler that combusts the finely divided biomass to generate water vapor. And a steam turbine rotated by the steam generated in the boiler , the blast machine has a container for hermetically storing the biomass, and a jacket provided on the outer periphery of the container, the steam generated in the boiler, Alternatively, a flow path through which steam flows after rotating the steam turbine, a supply path branched from the flow path and connected to a jacket, and a supply path for supplying steam of the flow path to the jacket and a flow path connected to the jacket and joined to the flow path And a return path for returning the steam that has flowed through the jacket to the flow path .

According to the method for producing pulverized biomass, the apparatus for producing pulverized biomass, and the boiler storage of the present invention, the pulverized biomass can be pulverized with a small amount of energy to form pulverized biomass as a fuel. By using the biomass, it is possible to reduce the operating cost of the boiler and improve the combustion efficiency.

It is a block diagram which shows the boiler apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the principal part of the boiler apparatus which concerns on the modification of this invention. It is a block diagram which shows the principal part of the boiler apparatus which concerns on another Example of this invention.

An embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the boiler device 1 of the present embodiment includes a coal-fired boiler 2 and is installed in a thermal power plant or the like. The coal-fired boiler 2 is, for example, a pulverized coal cooking boiler (PC boiler: Pulverized Coal boiler), and includes a furnace 2a, a superheater 2b which is a rear heat transfer section, a reheater 2c, and a coal-saving section 2d. There is. A denitration unit 4, an air heater 5, a dust collector 6, an induction fan 7, a heat exchanger 8, a desulfurization unit 9 and a pushing fan 10 are sequentially arranged in the exhaust gas processing flue 3 from the coal saving unit 2d to the stack P. Has been done.

The air heater 5 warms the external air introduced by the pushing fan 11 with the heat of the exhaust gas discharged from the denitration unit 4, and sends it to the burner unit 2e of the coal-fired boiler 2 as combustion air. The heat exchanger 8 exchanges heat between the exhaust gas guided by the attracting fan 7 and passing through the dust collector 6, and the exhaust gas introduced by the pushing fan 10 and passing through the desulfurization unit 9. The exhaust gas that has passed through the heat exchanger 8 is discharged from the chimney P.

The coal-fired boiler 2 is supplied with pulverized coal fuel obtained by pulverizing coal C by a mechanical mill (pulverizer) 20. This pulverized coal fuel is introduced into the furnace 2a of the coal-fired boiler 2 through the burner section 2e together with the combustion air introduced by the pushing fan 11, and is burned.

Steam generated by combustion of pulverized coal fuel in the coal-fired boiler 2 of the boiler device 1 is sent from the superheater 2b to the high-pressure turbine (steam turbine) 22 through the pipe 21 to rotate the high-pressure turbine 22. The steam used for the work of the high-pressure turbine 22 is returned to the reheater 2c through the pipe (flow path) 23 and is heated again. Then, the reheated steam is sent to the medium/low pressure turbine (steam turbine) 25 through the pipe 24, is used for the work of the medium/low pressure turbine 25, and then passes through the pipe 26 and the condenser 27. Returned to the coal-fired boiler 2.

Further, the boiler device 1 is provided with an explosion crusher 30 that pulverizes the biomass B by steam explosion to produce pulverized biomass as a biomass fuel. The biomass B is a solid fuel made of, for example, woody biomass. The blast machine 30 includes a steaming container (container) 30a with a jacket 30b. The jacket 30b is provided on the outer circumference of the steaming container 30a, and a branch pipe (supply path) 28 that branches from the pipe 23 is connected to the jacket 30b. A part of the steam (reheated steam) of 200 to 300° C. returning to the reheater 2 c of the coal-fired boiler 2 after rotating the high-pressure turbine 22 is introduced into the jacket 30 b through the branch pipe 28.

Further, a merging pipe (return path) 29 that joins the pipe 23 is connected to the jacket 30b on the downstream side of the branch point of the branch pipe 28 in the pipe 23. The steam that has flowed through the jacket 30b and has been used for heating the cooking container 30a and further the biomass B in the cooking container 30a is returned to the pipe 23 through the confluent pipe 29 and reused.
Hereinafter, steam explosion performed by the blast machine 30 of the boiler device 1 according to the present embodiment will be described.

First, after the biomass B is put into the cooking vessel 30a of the blast machine 30, the cooking vessel 30a is closed. The biomass B is, for example, wet biomass having a water content of about 30-60 wt %.
Next, a part of the reheated steam generated in the coal-fired boiler 2 by burning the pulverized coal fuel and the biomass fuel is introduced into the jacket 30b of the blast machine 30 via the branch pipe 28. That is, the steam is supplied only to the jacket 30b as a heating source of the steaming container 30a, and is not supplied to the steaming container 30a.

Next, the heat from the steam flowing through the jacket 30b is gradually transferred to the steaming container 30a, and the water content of the biomass B held in the steaming container 30a in a sealed state is gradually evaporated. As a result, steam is generated in the steaming container 30a, and only steam based on the water content of the biomass B is used for steam explosion of the biomass B.
The conditions of steam explosion in the cooking container 30a vary depending on the volume, shape, etc. of the cooking container 30a, but the cooking temperature is, for example, about 200 to 250° C., the holding time (sealing time) is, for example, about 10 to 30 minutes, and the cooking pressure ( The closing pressure) is about 1.6-4.0 MPa.

Next, the biomass B is indirectly heated by the steam flowing through the jacket 30b in a sealed state via the steaming container 30a, and the biomass B is steamed in the steaming container 30a only by the water content of the biomass B.
Next, after the holding time has elapsed, by opening a valve (not shown) provided in the cooking container 30a, the pressure in the cooking container 30a is instantly released, and rapid depressurization in the cooking container 30a is performed. A pulverized biomass fuel (for example, an average particle size of about 0.5 to 1.0 mm) is generated by steam explosion.

The produced biomass fuel is introduced into the furnace 2a of the coal-fired boiler 2 through the burner section 2e together with the combustion air introduced by the pushing fan 11, and is burned with the pulverized coal fuel pulverized by the mill 20.
As described above, in the present embodiment, the biomass B can be hermetically sealed and heated by the blast machine 30, and the biomass B can be steam-blasted with the water content of the biomass B to generate pulverized biomass. Therefore, pretreatment such as drying of the biomass B is unnecessary, and thus pretreatment equipment such as a dryer is not required, and energy consumption required for the pretreatment can be reduced.

In addition, by not supplying steam into the steaming container 30a, after the biomass B is charged into the steaming container 30a, steam explosion can be performed with the steaming container 30a sealed. Therefore, since only a small amount of condensed water based on the water content of the biomass B is generated by steam explosion, even if this condensed water is directly fed to the furnace 2a together with the finely divided biomass, it has a great influence on the combustion efficiency in the boiler 2. do not do.

Further, since the steam introduced into the jacket 30b does not come into contact with the biomass B, the steam introduced into the jacket 30b can be returned to the pipe 23 and reused as it is as the reheated steam of the coal-fired boiler 2. Therefore, post-treatment such as neutralization treatment, separation treatment, drainage treatment of condensed water generated by steam explosion is not required, so that post-treatment equipment is not required and energy consumption required for the post-treatment can be reduced. .. As described above, in the present embodiment, the biomass B can be pulverized with significantly less energy as compared with the conventional steam explosion, and the energy consumption and the facility cost in the boiler device 1 can be significantly reduced as a whole. The operating cost of the boiler device 1 can be reduced.

As shown in FIG. 2, a boiler device 1A according to a modified example of the present invention includes an oil-fired or gas-fired boiler 2A and a storage tank 32, and other configurations are the same as the boiler device 1 described in the above embodiment. Is the same. A liquid fuel such as petroleum or heavy oil or a gaseous fuel such as natural gas is transported and stored in the storage tank 32 via a pipe 33.

The liquid fuel or gas fuel stored in the storage tank 32, and the pulverized biomass produced in the steaming container 30a are introduced into the furnace 2a of the boiler 2A via the burner section 2e together with the combustion air introduced by the pushing fan 11. Is burned. Even in this case, the blast machine 30 can pulverize the biomass B with less energy. Further, since the boiler device 1A does not require the mill 20, the power consumption of the mill 20 can be reduced, and the energy consumption and equipment cost in the boiler device 1A can be further reduced.

As shown in FIG. 3, a boiler device 1B according to another modified example of the present invention includes a dryer (water content adjusting means) 34 that adjusts the water content of the pulverized biomass produced by the blast machine 30, and other configurations. Is the same as the boiler device 1A described in the previous modification. A part of the steam generated in the oil-cooked or gas-cooked boiler 2B is introduced into the dryer 34 through the branch pipe 28.

Here, it is assumed that the biomass B charged into the steaming container 30a is, for example, brown coal biomass having a water content of about 90 wt %. In this case, compared with the case of using the biomass B having a water content of about 30-60 wt% described in the above embodiment, more condensed water is generated in the cooking container 30a based on the water content of the biomass B. Become. If this condensed water is introduced into the furnace 2a as it is together with the pulverized biomass, the combustion efficiency in the boiler 2B is affected to a considerable extent.

Therefore, the pulverized biomass generated in the steaming container 30a is dried in the dryer 34 and then introduced into the furnace 2a, so that the boiler 2B can be supplied with the pulverized biomass having a high water content as it is into the furnace 2a. Combustion efficiency can be improved. Moreover, since the heating source of the pulverized biomass in the dryer 34 uses the steam generated in the oil-cooked or gas-cooked boiler 2B, it is possible to reduce energy consumption and equipment cost in the boiler device 1B.

The description of the embodiment and the modified example of the present invention is finished above, but the present invention is not limited to these and various modifications can be made without departing from the spirit of the present invention.
For example, the dryer 34 shown in the modification of FIG. 3 may be provided in the boiler device 1 of the embodiment shown in FIG. In this case, even when wet biomass having a relatively high water content is used as the biomass raw material, it is possible to suppress a decrease in the combustion efficiency of the boiler 2 due to the condensed water generated in the cooking vessel 30a.

Further, the pulverized biomass generated in the steaming container 30a may be further finely pulverized by a mill (not shown) and then put into the furnace 2a for combustion. In this case, since the biomass after steam explosion is embrittled by the heat treatment and is in a state of being easily crushed, more pulverized biomass can be obtained by further crushing with a mill.
Further, by providing a classifier (not shown), the pulverized biomass may be returned to the blasting machine 30 until it is miniaturized to a size not exceeding a predetermined threshold value, repeatedly crushed, and then charged into the furnace 2a.

Moreover, in the said embodiment and modification, the case where pulverized biomass was produced|generated only by the water content of the biomass B by steam-blasting with the blasting machine 30 with which each boiler apparatus 1, 1A, 1B is demonstrated. In this case, a part of the reheated steam (steam returned to the reheater 2c after rotating the high-pressure turbine 22) out of the high-temperature steam generated in each boiler 2, 2A, 2B is partially steamed in the cooking vessel 30a or It is used as a heat source for the dryer 34. As a result, the biomass B can be pulverized with a small amount of energy without requiring new power consumption. However, the heating source is not limited to this, and steam that has been used for the work of the medium/low pressure turbine 25 may be used, or steam generated in each of the boilers 2, 2A and 2B may be directly used. Alternatively, the exhaust gas generated in each boiler 2, 2A, 2B may be reheated with steam and used.

In addition, a pulverized biomass production apparatus in the form of the blasting machine 30 is provided in equipment and facilities other than the boiler apparatuses 1, 1A, and 1B, and the cooking vessel 30a is heated by using a heating source other than steam. Finely divided biomass may be produced.
Further, the biomass capable of being pulverized in the present invention may be any moistened biomass containing water, and may be not only wood-based biomass but also unused biomass including plant-based biomass or waste-based biomass. good.

1,1A,1B Boiler device 2 Coal-fired boiler (boiler)
2A, 2B Oil-fired or gas-fired boiler (boiler)
21,23,24,26 Piping (flow path)
22 High-pressure turbine (steam turbine)
25 Middle/low pressure turbine (steam turbine)
28 Branch piping (supply path)
29 Combined piping (return path)
30 Blast machine 30a Steaming container (container)
30b jacket 34 dryer (water content adjusting means)
B biomass

Claims (9)

An explosion process in which the biomass is hermetically sealed and heated, and the biomass is steam-explosed with the water content of the biomass to generate a finely divided biomass ,
And a water content adjusting step of adjusting the water content of the pulverized biomass. The method for producing finely divided biomass according to claim 1 , wherein in the blasting step, the biomass is heated by steam without contact. Further comprising, a manufacturing method of micronized biomass according to claim 1 or 2 grinding step for mechanically grinding the pulverized biomass. The biomass is hermetically sealed, heated, and equipped with a crusher that steam-blasts the biomass with the moisture content of the biomass to generate pulverized biomass.
The blaster is
A container for hermetically containing the biomass,
A heating source for indirectly heating the biomass by heating the container ,
An apparatus for producing finely divided biomass, comprising: a water content adjusting means for adjusting the water content of the finely divided biomass. The said heating source is a manufacturing apparatus of the micronized biomass of Claim 4 which is steam which heats the said biomass non-contact. The apparatus for producing finely divided biomass according to claim 4 , further comprising a pulverizer that mechanically pulverizes the finely divided biomass. A crusher that closes and heats the biomass and steam-blasts the biomass with the water content of the biomass to generate pulverized biomass,
A boiler that burns the pulverized biomass to generate steam,
A steam turbine rotated by steam generated in the boiler ,
The blaster is
A container for hermetically containing the biomass,
A jacket provided on the outer periphery of the container
Equipped with,
Steam generated in the boiler, or a flow path of steam after rotating the steam turbine,
A supply path branched from the flow path and connected to the jacket, and supplying water vapor of the flow path to the jacket,
A return path that is connected to the jacket and merges with the flow path, and returns the steam that has flowed through the jacket to the flow path.
A boiler device further comprising: The boiler apparatus according to claim 7 , further comprising a water content adjusting unit that adjusts a water content of the pulverized biomass. The boiler apparatus according to claim 7 or 8 , further comprising a grinder that mechanically grinds the pulverized biomass.

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