JP2017105920A - Manufacturing method of bamboo for fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of bamboo capable of effectively being used as a main fuel for large scale power generation by direct combustion (bamboo for fuel) by reducing potassium content.SOLUTION: The manufacturing method of bamboo for fuel includes a process for cutting the bamboo (cutting process), a process for impregnating the cut bamboo into water (impregnation process) and a process for taking the impregnated bamboo off from water and drying the same (drying process) and temperature of water in the impregnation process is in a range of 50 to 100°C.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing fuel bamboo.

  In recent years, the use of biomass fuel has been expanded from the viewpoint of preventing global warming. Biomass is a concept that expresses the mass of biological resources (bio). In general, “renewable, biological organic resources excluding fossil resources” are called biomass. Biomass types include waste biomass, unused biomass, and resource crops (plants grown for the purpose of producing energy and products). Examples of waste-based biomass include discarded paper, livestock excrement, food waste, construction generated wood, lumber mill residue, sewage sludge, etc., and examples of unused biomass include rice straw, straw, Rice husk etc. are mentioned, and examples of resource crops include sugar cane and corn.

  These biomasses are usually difficult to use as effective fuels as they are. Therefore, various processing techniques for making these biomass high-quality biomass fuels have been proposed. For example, Patent Document 1 proposes an apparatus and a method for efficiently removing foreign matters without reducing the yield of raw materials including piss in cleaning biomass raw materials such as bagasse. Further, for example, Patent Document 2 discloses a biomass cleaning method and a biomass charcoal production method that can produce biomass charcoal having a low alkali metal content even when the biomass contains an alkali metal such as potassium or sodium. And, a method of operating a vertical furnace has been proposed. In addition, for example, in Patent Document 3, when using herbaceous biomass as a fuel, a gasification raw material, or a carbide raw material, a herbaceous system that can prevent the occurrence of problems caused by potassium contained in the herbaceous biomass. Biomass pretreatment apparatuses and pretreatment methods have been proposed. Further, for example, Patent Document 4 proposes a method for severe steam explosion, and at the same time a method for producing a product having a low furfural.

JP 2011-245383 A JP 2010-270320 A JP 2012-153790 A Special table 2012-522099 gazette

  Among the biomass, bamboo contains an extremely large amount of potassium in the ash after burning. The potassium in the ash may cause, for example, a drop in the melting point of the ash and cause corrosion of the furnace material. For this reason, bamboo is not currently used as the main fuel for large-scale (MWh class) power generation by direct combustion, and no proposal has been made to achieve this. On the other hand, bamboo forests that are neglected in Japan are said to be 160,000 ha, and if bamboo can be effectively used as the main fuel for large-scale power generation by direct combustion, it is a promising means for solving energy problems. Can be.

  Then, this invention aims at providing the manufacturing method of the bamboo material (bamboo material for fuel) which can reduce the potassium content and can be effectively used as a main fuel of large-scale power generation by direct combustion.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a bamboo material having a reduced potassium content can be obtained by a production method including a specific process, and have completed the present invention.

That is, the present invention is as follows.
[1]
The process of cutting bamboo (cutting process),
Including a step of immersing the cut bamboo material in water (immersion step), and a step of taking out the immersed bamboo material from water and drying it (drying step),
The manufacturing method of the bamboo material for fuels whose temperature of the water in the said immersion process is the range of 50-100 degreeC.
[2]
The method for producing a bamboo for fuel according to [1], wherein water is stirred in the dipping step.
[3]
A biomass power generation material obtained by the production method according to [1] or [2].
[4]
The biomass power generation system which uses the bamboo material obtained by the manufacturing method as described in [1] or [2] as a fuel.

  According to the present invention, it is possible to efficiently reduce the potassium content in bamboo, and it is possible to effectively use bamboo as a main fuel for large-scale power generation by direct combustion.

It is a graph which shows an example of the change of the electrical conductivity in the immersion process whose water temperature is 60 degreeC. It is a graph which shows an example of the change of the electrical conductivity in the immersion process of water temperature 45 degreeC. It is a graph which shows an example of the change of the electrical conductivity in the immersion process of water temperature 30 degreeC. It is a graph which shows an example of the change of K elution amount (estimation by KCl conversion) in the immersion process of water temperature 60 degreeC. It is a graph which shows an example of the change of K elution amount (estimation by KCl conversion) in the immersion process of water temperature 45 degreeC. It is a graph which shows an example of the change of K elution amount (estimation by KCl conversion) in the immersion process of water temperature 30 degreeC. It is a graph which shows an example of the change of the estimation K removal rate (estimation by KCl conversion) in the immersion process of the water temperature of 60 degreeC. It is a graph which shows an example of the change of the estimation K removal rate (estimation by KCl conversion) in the immersion process of the water temperature of 45 degreeC. It is a graph which shows an example of the change of the estimation K removal rate (estimation by KCl conversion) in the immersion process of water temperature 30 degreeC. It is a graph which shows an example of the change of the potassium ion elution amount per 1 kg of bamboo in the predetermined time during immersion in an immersion process. It is a graph which shows an example of the change of K elution amount (estimation by KCl conversion) in the immersion process of water temperature 60 degreeC. It is a graph which shows an example of the change of K elution amount (estimation by KCl conversion) in the immersion process of water temperature 45 degreeC. It is a graph which shows an example of the change of K elution amount (estimation by KCl conversion) in the immersion process of water temperature 30 degreeC. It is a calibration curve for calculating the estimated K elution amount. It is the schematic which shows the structure of a biomass power generation system clearly. It is a figure which shows the structural example of the whole biomass power generation system. It is a figure which shows the connection of each structure in a biomass power generation system, and flows, such as fuel and water. It is the figure seen from the back side of the system shown in FIG. 15 etc. which shows the structural example of a fuel supply apparatus (multi-screw feeder). It is the figure seen from the back side of the system shown in FIG. 15 etc. which shows the structural example of a grate.

  Hereinafter, a mode for carrying out the present invention (hereinafter abbreviated as “this embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

The method for producing the bamboo for fuel of this embodiment is as follows:
The process of cutting bamboo (cutting process),
Including a step of immersing the cut bamboo material in water (immersion step), and a step of taking out the immersed bamboo material from water and drying it (drying step),
The temperature of water in the immersion step is in the range of 50 to 100 ° C.
Since the bamboo content obtained by such a manufacturing method has a reduced potassium content, when burned, the melting point drop of ash due to potassium is suppressed and corrosion of the furnace material can be suppressed. Therefore, the bamboo material obtained by the manufacturing method of this embodiment can be effectively used as a main fuel for large-scale power generation by direct combustion.

  In addition, in this embodiment, the bamboo material for fuel means the bamboo material used as biomass fuel.

[Cutting process]
The method for manufacturing a bamboo material for fuel according to this embodiment includes a step of cutting the bamboo material (cutting step).

  The method of cutting the bamboo is not particularly limited, and examples thereof include a method of cutting with a saw or an electric saw, a method of breaking with a bamboo cracker, crushing with a crusher, and crushing with a crusher.

  Although it does not specifically limit as a shape of the bamboo material after a cutting | disconnection, For example, a split bamboo, a chip | tip, a round bamboo, and sawdust are mentioned. Of these, split bamboo and chips are preferable, and chips are more preferable.

  When the bamboo material is cut as described above, potassium tends to be eluted from the bamboo material into the water in the dipping process described later, and since the bamboo hollow portion is reduced or eliminated, the bamboo material is easily submerged in the water. It becomes easy to soak.

[Immersion process]
The method for manufacturing a bamboo material for fuel according to this embodiment includes a step (immersion step) of immersing the bamboo material cut in the cutting step in water.

  The method for immersing the bamboo material in water is not particularly limited, and examples thereof include a method in which the entire bamboo is completely immersed.

  In the immersion step, it is preferable to stir water. Specific examples of the stirring method are not particularly limited, and examples thereof include a stirring blade, a circulation pump, and aeration.

  When water is stirred as described above, potassium tends to be more easily eluted from the bamboo into the water in the dipping process.

  The temperature of the water in the immersion step is in the range of 50 to 100 ° C, preferably in the range of 50 to 80 ° C, more preferably in the range of 60 to 80 ° C, and in the range of 60 to 70 ° C. More preferably it is. When the temperature of water in the dipping step is within the above range, potassium is eluted from the bamboo into the water in the dipping step, and a bamboo material with a sufficiently reduced potassium content is obtained.

  Although it does not specifically limit as water in the said immersion process, For example, cation exchange water, tap water, fresh water (river water), spring water (hot spring water) is mentioned. Among these, cation exchange water and tap water are preferable, and cation exchange water is more preferable.

In the dipping step, the removal rate of potassium from bamboo can be determined from the following equation by measuring the amount of potassium eluted.
Potassium removal rate (%) = potassium elution amount in water in dipping process / potassium content in bamboo before dipping process × 100

  Therefore, in order to obtain bamboo material from which potassium has been sufficiently removed in the dipping step, it is preferable to measure the amount of potassium eluted and to grasp the removal rate of potassium from the bamboo material. Moreover, in the said immersion process, since the electrical conductivity of water correlates with the elution amount of potassium, you may grasp | ascertain the removal rate of potassium from bamboo by measuring the electrical conductivity of water. .

  In the dipping step, the dipping time is not particularly limited as long as the removal rate of potassium from the bamboo is within the above range, and is, for example, 0 minutes to 1 day.

[Drying process]
The method for manufacturing a bamboo material for fuel according to this embodiment includes a step (drying step) of taking out the bamboo material dipped in the dipping step from water and drying it.

  Although it does not specifically limit as a method of drying bamboo material, For example, airflow drying, warm air drying, steam drying, dehumidification drying, vacuum drying, smoking drying, and natural drying are mentioned.

  The water content in the bamboo after the drying step is preferably 25 to 40% by weight, more preferably 25 to 35% by weight, and further preferably 30 to 35% by weight.

  The bamboo material for biomass fuel of this embodiment is a bamboo material obtained by the above-described manufacturing method. The bamboo material for biomass fuel according to the present embodiment has a reduced potassium content, and can therefore be used effectively as a main fuel for biomass power generation.

<Biomass power generation system>
The biomass power generation system of this embodiment uses bamboo material obtained by the above-described manufacturing method as fuel.

Moreover, the biomass power generation system of this embodiment is
A combustion furnace into which primary air for efficiently burning fuel on the grate, and unburned matter generated on the grate, and secondary air for secondary combustion of unburned gas;
A water pipe for cooling the furnace wall of the combustion furnace to lower the temperature;
With
Reducing the flow rate of the primary air,
Cooling the furnace wall of the combustion furnace with cooling water flowing through the water pipe,
It is preferable to burn bamboo material obtained by the above-described manufacturing method as the fuel.

  According to this biomass power generation system, it is possible to further suppress slag adhesion to the furnace wall when the bamboo material obtained by the above-described manufacturing method is burned. Therefore, the bamboo material obtained by the above manufacturing method can be effectively used as the main fuel.

  Hereinafter, preferred embodiments of the biomass power generation system of the present embodiment will be described in detail with reference to the drawings (see FIGS. 15 to 19).

  15 to 19 show an embodiment of the biomass power generation system of the present embodiment. FIG. 15 is a schematic diagram showing the configuration of the biomass power generation system in an easy-to-understand manner, FIG. 16 is a diagram showing an example of the overall configuration of the biomass power generation system, and FIG. 17 shows the connections between the components in the biomass power generation system and the flow of fuel, water, etc. FIG. 18 is a diagram illustrating a configuration example of a fuel supply device (multi-screw feeder), and FIG. 19 is a perspective view illustrating a configuration example of a grate.

  The biomass power generation system 1 uses, for example, bamboo material obtained by the above-described manufacturing method as a main fuel, and performs pyrolysis and carbonization as necessary in a state where waste biomass such as woody biomass and municipal waste is included in the fuel. This is a system for generating electricity by operating the generated gas as energy and burning it in a combustor. The biomass power generation system 1 of the present embodiment can be divided into the following eight units if functionally classified.

<First unit 10>
A unit that transports and prepares fuel. The first unit 10 includes an unloading place 11 and a temporary fuel storage place 13 (see FIG. 15).

  The unloading place 11 is a place where the biomass fuel transported by the tractor TR or the like is unloaded (see FIG. 15). The unloaded biomass fuel is shredded by a shredder device when necessary and stored in a temporary storage place 13. In the case of the biomass power generation system 1 of the present embodiment that uses bamboo material obtained mainly by the above-described manufacturing method as biomass, raw materials for bamboo material such as crushed bamboo chips are stored. Finally, the fuel is moved to the fuel storage 21, and other stones, sand, mud, etc. are used for road pavement materials, for example.

<Second unit 20>
The unit where combustion is stored. The second unit 20 includes a fuel storage 21 having a moving floor and a conveyor 23 to the fuel supply system.

  The fuel storage 21 stores biomass fuel. The fuel storage 21 has a capacity capable of holding fuel for a required operation time so that fuel does not need to be replenished on the way. The stored biomass fuel is automatically carried out by the hydraulically controlled floor and chain conveyor controlled by the fuel supply system, and conveyed to the third unit 30 by the conveyor 23.

<Third unit 30>
The third unit 30 is a boiler system. The third unit 30 includes fuel supply devices 31A and 31B, a combustion furnace 32, a boiler 34, an internal pipe 35, a boiler cleaning device (not shown), an economizer 37, a super heater 38, and a water pipe 39.

  The fuel supply devices 31 </ b> A and 31 </ b> B are devices that supply fuel to the combustion furnace 32. In this embodiment, the fuel conveyed by the conveyor 23 is supplied to the combustion furnace 32 using a spiral multi-screw feeder (see FIGS. 15 and 18). Although not specifically shown, in order to prevent backfire, the supply system has a fire extinguishing unit designed with redundancy.

  The combustion furnace 32 is a furnace for burning supplied biomass fuel, and is designed as a stoker-type combustion furnace in which appropriate air is supplied to the furnace of the inclined grate 33. The structure of the combustion furnace 32 is impermeable to gas and can support the weight of the inner wall and equipment of the furnace. Depending on the size, several inspection and maintenance doors are provided. Although not shown in particular, the combustion furnace 32 is lined with a multilayer inner wall. For example, a high alumina castable (refractory material) or a refractory brick is used as a front layer in a high load place. Low-cement materials are used in low-load areas. The middle layer uses common refractory bricks and castables, and the outer layer uses thermal insulation. Depending on the size, the combustion furnace 32 is often lined at the factory.

  Further, in the combustion furnace 32, by recirculating the exhaust gas, not only wet fuel can be used, but also combustion temperature control for minimizing NOx emission can be performed. Combustion is always controlled in consideration of the state of load and pressure, and the ratio of excess air (λ control).

  The grate 33 is self-supporting and is placed in the combustion furnace 32, and its dimensions are determined at the design stage (see FIG. 19). Several hydraulic cylinders move the rods of the grate 33 back and forth to completely burn the fuel. Incombustibles (ash and other things) move on the grate 33 and are discharged from the end of the combustion furnace 32 by the discharge conveyor (externally through the discharge hole).

  In the biomass power generation system 1 of the present embodiment, primary air and secondary air are supplied to the fuel placed on the grate 33 and burned (see FIG. 16). That is, in order to efficiently burn the fuel on the grate 33, primary air is blown from below the grate 33, and secondary air is used to cause secondary combustion of unburned gas and unburned matter generated on the grate 33. In order to prevent clinker from adhering to the wall surface.

  A more specific description will be given with reference to FIG. In the stoker-type combustion furnace 32, primary air A is supplied from the bottom of the grate 33 to the primary combustion chamber above the grate 33 to cause primary combustion of the fuel on the grate 33, and the secondary above the primary combustion chamber. The secondary air B is supplied to the combustion chamber, the unburned gas and unburned matter generated in the primary combustion chamber are secondarily burned, and the combustion gas is discharged from the upper part of the post-combustion grate 33 (the exhaust gas after passing through the dust collector). ) Partially withdrawn and blown it into the secondary combustion chamber to form a reduction zone to reduce NOx, and then reduce CO and dioxins at a high temperature by secondary combustion and at the same time realize low air ratio combustion To do. The primary air A is air (normal air) supplied from the boiler 34, and the primary air A ′ is recirculated air. The primary air A ′ is used for fuel reduction and drying.

  The boiler 34 is disposed in the middle of the internal pipe 35, and heats the circulating water by exchanging heat between the combustion exhaust gas and the circulating water. A boiler cleaning device (not shown) cleans the used boiler 34. The third unit 30 further includes a soot blower (soot) using steam for online cleaning of the super heater 38 and the economizer 37.

  The economizer 37 is one of the feed water heaters of the boiler 34, and heats the feed water using the residual heat of the exhaust. The economizer 37 is configured by a water pipe or the like provided in the flue 36.

  In the biomass power generation system 1, most of the ash in the combustion gas is removed at the part of the enclosure C shown in a cloud shape in FIG. 16. This is because a large amount of ash is collected through the duct of the downdraft (see FIG. 16). Further, in the subsequent upward air flow to the super heater 38, only very small fine powder remains, so that the amount of clinker adhering to the pipe of the super heater 38 can be reduced.

  The water pipe 39 is a pipe for flowing cooling water to cool the furnace wall of the combustion furnace 32, and is arranged around the flue 36. Although the specific configuration of the water pipe 39 is not particularly limited, the water pipe 39 in the biomass power generation system 1 of the present embodiment is mostly a horizontal water pipe 39a arranged horizontally, a vertical water pipe 39b connecting these horizontal water pipes 39a, and It includes a fine water pipe 39c that stops halfway (see FIG. 16 and the like).

<Fourth unit 40>
The 4th unit 40 is a unit which processes combustion gas. The fourth unit 40 includes a primary dust collector 41, an electrostatic dust collector 42, a ventilation fan 43, and a chimney 45.

  The primary dust collector 41 that removes coarse particles is connected to the flue 36 after passing through the economizer 37. Next, the coarsely collected exhaust gas is further collected by the electrostatic dust collector 42. The separated dust is continuously removed, and the cleaned exhaust gas is guided to the steel chimney 45 through the ventilation fan 43. The chimney 45 is self-supporting, and the height is designed in accordance with the height required by the municipality of the installation location.

<Fifth unit 50>
The 5th unit 50 is a unit which constitutes a power generator. The fifth unit 50 includes a condensing turbine 51, a steam condenser 52 and a condensate tank 53, an air cooler 54, and an external pipe 55 that are gear-connected to the generator 56.

  In the fifth unit 50, the condensing turbine 51 is rotated by superheated steam produced by the boiler 34. If steam is extracted from the condensing turbine 51, it can be used for various purposes (for example, processing, heating). The condensed steam after use is collected in the non-pressure condensate tank 53 and then returned to the BFW (boiler supply water) tank 63. The vapor condenser 52 is connected to the condensation tank.

<Sixth unit 60>
The sixth unit 60 is a unit that performs water treatment. The sixth unit 60 includes a fresh water treatment device 61, a deaeration device 62, a BFW (boiler supply water) tank 63, an instrumented BFW pump 64, and a drain pipe system 65.

  A chemical water treatment system is composed of a cation (cation) exchanger and a reverse osmosis system. The BFW tank 63 is composed of a thermal degassing device and instrumentation therein.

<Seventh unit 70>
The seventh unit 70 is a unit that performs ash treatment. The seventh unit 70 includes an ash extraction device 71 from the grate 33, an ash extraction from the middle of the flue 36, an ash extraction device 73 from the primary dust collector 41 and the electrostatic dust collector 42.

  The ash of the grate 33 in the combustion furnace 32 is taken out from the lower part at the end of the combustion furnace 32. Ashes from the middle of the flue 36 are carried to a common ash removal position. The ash of the primary dust collector 41 and the electrostatic dust collector 42 is directly taken out from a take-out port (hopper) of a case (not shown). The boundary of the ash treatment system becomes the take-off nozzle of the corresponding rotary valve. Each ash is collected separately from each outlet and delivered to an industrial waste disposal contractor.

<Eighth unit 80>
The eighth unit 80 is a unit constituting the control device. The eighth unit 80 includes a control panel 81, an I & P field device (hereinafter, not shown), a combustion control device, and a boiler control device (see FIG. 17).

  Subsequently, in the biomass power generation system 1 described above, a method of burning when bamboo material obtained by the above-described manufacturing method is used as a main fuel will be described (see FIG. 17 and the like).

  In burning bamboo material obtained by the above-described manufacturing method as a main fuel, combustion is performed while the flow rate of primary air is reduced and the furnace wall of the combustion furnace 32 is cooled by cooling water flowing through the water pipe 39. Thereby, the slag adhesion to the furnace wall at the time of burning bamboo can be suppressed.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited only to these Examples.

[Measurement method of electrical conductivity]
The electrical conductivity of water in the dipping process was measured with an electrical conductivity meter.

[Measurement method of potassium ion concentration]
The potassium ion concentration in water in the dipping process was measured with a potassium ion meter.

[Calculation method of potassium elution amount (estimated value)]
The amount of potassium dissolved in water (estimated value) in the dipping process was calculated from the following equation using a calibration curve (see FIG. 14) representing the relationship between the potassium ion concentration of potassium chloride (KCl) in water and the electrical conductivity. .
Potassium elution amount at a predetermined immersion time (estimated value) (mg / kg) = (electric conductivity of water at a predetermined immersion time (μS / cm) −electric conductivity of water before the immersion step (μS / cm)) × 0.2631 × Weight of water used in the immersion process (kg) / Bamboo dry weight (kg)

[Calculation method of potassium removal rate]
The potassium removal rate from the bamboo material in the dipping process is the following as the potassium content in the bamboo material before the dipping process is the proportion (59% by weight) of potassium in the ash of Comparative Example 1 described below (when the dipping process is not performed). Calculated from the formula.
Potassium removal rate (%) = potassium elution amount / (weight of ash × 0.59) × 100

[Make bamboo]
Bamboo harvested from bamboo forest (Mosouchiku, length: 15.78m, weight: 42.94kg (without branches), root diameter: 13cm, moisture content: 44.9% by weight) cut at intervals of 20cm or 1m And made round bamboo.

[Comparative Example 1]
The prepared round bamboo (length: 20 cm, diameter: 7.2 cm, weight: 389.4 g) was dried for one day with a thermostat (135 ° C.). The dried round bamboo (weight: 214.5 g) was fired twice at 900 ° C. for 1 hour. The weight of the ash after baking was 2.3341 g, and the proportion of potassium in the ash was 59% by weight. As described above, since the round bamboo contains an extremely large amount of potassium in the ash after being baked, when used as a fuel, the potassium in the generated ash causes, for example, a drop in the melting point of the ash, causing corrosion of the furnace material. It is thought that there is a risk of inviting.

[Example 1]
The prepared round bamboo (length: 21 cm, diameter: 7.7 cm, weight: 449.9 g) was left for 3 days. The bamboo after leaving it was cut to create a split bamboo. The prepared split bamboo (weight: 421.0 g) was immersed in 60 ° C. cation exchange water (6 kg) for 1 hour without stirring. After immersion, the bamboo was taken out of the water and dried for one day with a thermostat (135 ° C.) to prepare a bamboo material for fuel. The prepared bamboo for fuel (weight: 252.0 g) was fired twice at 900 ° C. for 1 hour. The weight of the ash after baking was 2.1962 g. As can be seen from FIGS. 1, 4 and 7, the bamboo material for fuel has a reduced potassium content in the ash, so when used as a fuel, for example, the melting point drop of ash due to potassium is suppressed, Corrosion of the furnace material can be suppressed.

[Examples 2 to 4 and Comparative Examples 2 to 9]
As shown in Table 1, a bamboo material for fuel was prepared in the same manner as in Example 1 except that the immersion time and the immersion temperature were changed. Each prepared bamboo for fuel was fired twice under the condition of 900 ° C. for 1 hour. Table 2 shows the weight of the ash after firing in each fuel bamboo material. Moreover, since the bamboo material for fuels of Examples 1-4 is reduced in potassium content in ash compared with the bamboo material for fuels of Comparative Examples 2-9, as can be seen from FIGS. When used as, for example, the melting point drop of ash due to potassium is suppressed, and corrosion of the furnace material can be suppressed. In Example 4 and Comparative Examples 8 and 9, the electrical conductivity of water at a predetermined time during immersion was measured, and the estimated potassium elution amount and the estimated potassium removal rate were calculated. The results are shown in Tables 3-5.

[Example 5]
The prepared round bamboo (length: 20.2 cm, diameter: 8.6 cm, weight: 499.3 g) was left for 6 days. The bamboo after leaving it was cut to create a split bamboo. The prepared split bamboo (weight: 425.5 g) was immersed in 60 ° C. cation exchange water (6 kg) for 1 hour with stirring. After immersion, the bamboo was taken out of the water and dried for one day with a thermostat (135 ° C.) to prepare a bamboo material for fuel. The prepared bamboo for fuel (weight: 267.2 g) was fired twice at 900 ° C. for 1 hour. The weight of the ash after baking was 2.4932 g. As can be seen from FIG. 1, FIG. 4 and FIG. 7, the bamboo material for fuel has a reduced potassium content in the ash after being fired. Is suppressed, and corrosion of the furnace material can be suppressed.

[Examples 6 to 8 and Comparative Examples 10 to 17]
As shown in Table 6, a bamboo material for fuel was prepared in the same manner as in Example 5 except that the immersion time and the immersion temperature were changed. Each prepared bamboo for fuel was fired twice under the condition of 900 ° C. for 1 hour. Table 7 shows the weight of the ash after firing in each fuel bamboo material. As can be seen from FIGS. 1 to 9, the bamboo materials for fuel of Examples 5 to 8 are used as fuel because the potassium content in the ash is reduced as compared with the bamboo materials for fuel of Comparative Examples 10 to 17. Then, for example, a drop in melting point of ash due to potassium is suppressed, and corrosion of the furnace material can be suppressed. In Example 8 and Comparative Examples 16 and 17, the electrical conductivity of water at a predetermined time during immersion was measured, and the estimated potassium elution amount and the estimated potassium removal rate were calculated. The results are shown in Tables 8-10.

[Example 9]
The created round bamboo (length: 1 m) was processed into a chip shape (length: 10 cm). The processed chip-shaped bamboo (weight: 369.3 g) was immersed in 50 ° C. cation exchange water (6 kg) for 3 hours with stirring. After immersion, the chip-shaped bamboo was taken out of the water and dried for one day with a thermostatic machine (135 ° C.) to prepare a bamboo material for fuel. The prepared bamboo for fuel (weight: 191.9 g) was fired twice at 900 ° C. for 1 hour. The weight of the ash after baking was 1.9568 g. As can be seen from FIGS. 10 and 11, the bamboo material for fuel has a reduced potassium content in the ash, so when used as a fuel, for example, the melting point drop of ash due to potassium is suppressed, and the corrosion of the furnace material Can be suppressed. In Example 9, the electrical conductivity of water at a predetermined time during immersion was measured, and the estimated potassium elution amount and the estimated potassium removal rate were calculated. The results are shown in Table 13. Moreover, the potassium ion elution amount per 1 kg of bamboo in a predetermined time during the immersion was measured. The results are shown in FIG.

[Examples 10 to 12 and Comparative Examples 18 to 20]
As shown in Table 11, a bamboo material for fuel was prepared in the same manner as in Example 9 except that the immersion temperature was changed. Each prepared bamboo for fuel was fired twice under the condition of 900 ° C. for 1 hour. Table 12 shows the weight of the ash after firing in each fuel bamboo. As can be seen from FIG. 10, FIG. 12 and FIG. 13, the bamboo material for fuel produced in Examples 10-12 has a reduced potassium content in ash, so when used as fuel, for example, It is considered that the melting point drop is suppressed and the corrosion of the furnace material can be suppressed. On the other hand, the bamboo material for fuels produced in Comparative Examples 18 to 20 is not sufficiently reduced in potassium content in ash. Therefore, when used as fuel, for example, a drop in melting point of ash due to potassium occurs, and It is thought that corrosion progresses. In Examples 10 to 12 and Comparative Examples 18 to 20, the electrical conductivity of water at a predetermined time during immersion was measured, and the estimated potassium elution amount was calculated. The results are shown in Tables 14-19. Moreover, the potassium ion elution amount per 1 kg of bamboo in a predetermined time during the immersion was measured. The results are shown in FIG.

  Since the bamboo content obtained by the production method of the present invention has a reduced potassium content, it can be suitably used as a main fuel for large-scale power generation by direct combustion.

DESCRIPTION OF SYMBOLS 1 ... Biomass power generation system 10 ... 1st unit 11 ... Unloading place 13 ... Temporary storage place 20 ... 2nd unit 21 ... Fuel storage 23 ... Conveyor 30 ... 3rd unit 31A ... Fuel supply apparatus 31B ... Fuel supply apparatus 32 ... Combustion Furnace 33 ... Grate 34 ... Boiler 35 ... Internal piping 36 ... Flue 37 ... Economizer 38 ... Super heater 39 ... Water pipe 39a ... Cross water pipe 39b ... Vertical water pipe 39c ... Fine water pipe 40 ... Fourth unit 41 ... Primary dust collector 42 ... Electrostatic dust collector 43 ... Ventilation fan 45 ... Chimney 50 ... Fifth unit 51 ... Condensing turbine 52 ... Steam condenser 53 ... Condensate tank 54 ... Air cooler 55 ... External piping 56 ... Generator 60 ... Sixth unit 61 ... Fresh water Processor 62 ... Deaerator 63 ... BFW (boiler supply water) tank 64 ... BFW pump 65 with instrumentation ... Drainage pipe system 70 ... 7 unit 71 ... ash extraction device 80 ... eighth unit from the ash removal device 73 ... primary dust collector 41 and the electrostatic precipitator 42 from the grate 33 81 ... control panel

Claims (4)

The process of cutting bamboo (cutting process),
Including a step of immersing the cut bamboo material in water (immersion step), and a step of taking out the immersed bamboo material from water and drying it (drying step),
The manufacturing method of the bamboo material for fuels whose temperature of the water in the said immersion process is the range of 50-100 degreeC.   The manufacturing method of the bamboo material for fuels of Claim 1 which stirs water in the said immersion process.   Bamboo material for biomass fuel obtained by the production method according to claim 1 or 2.   The biomass power generation system which uses the bamboo material obtained by the manufacturing method of Claim 1 or 2 as a fuel.