JP5531289B2 - Method for producing bamboo pellet fuel - Google Patents

Description

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

  Conventionally, as pellet fuel, waste paper is used as a raw material, wood-based, that is, wood scrap, sawdust generated during lumber processing, sawdust, kana scrap, etc. are known (for example, patent documents) 1 etc.). Pellets made from waste paper are difficult to maintain their shape after molding, are easily moist, and have a problem that the amount of generated heat is lower than that of conventional fossil fuels such as petroleum. Similarly, wood-based pellets have a problem that the amount of heat generated is lower than that of petroleum and the supply capacity of materials is low. Furthermore, wood pellets have a large variation in the amount of heat generated, a large amount of ash and clinker during fuel, and there are problems in manufacturing and quality.

  Meanwhile, the problem of abandoned bamboo forests has been taken up nationwide in recent years. Traditionally, bamboo has been useful as a production material, but with the advent of alternative products, demand has gradually declined and coupled with the growth and reproductive power of bamboo, abandoned bamboo forests are expanding nationwide. Therefore, as a countermeasure against such abandoned bamboo forest, effective use of bamboo (for example, blending into livestock feed by bamboo charcoal, bamboo fine powder, etc.) has been attempted, but the scale is still small. is there.

JP 2004-53141 A

  Bamboo is known to generate more heat (4 to 33%) than wood, and has been regarded as a promising fuel. For example, wood is 3600-4600 kcal / kg, while bamboo is 4700-4800 kcal / kg. However, bamboo has the following characteristics and issues, and cannot be used as it is for pellet fuel.

(1) Bamboo begins to ferment immediately after the crushing and pulverization process of pellet production, solidifies, and mold adheres. When solidified by fermentation, it is necessary to loosen the crushed and crushed pieces that have hardened during the drying and molding steps. If mold adheres, it causes quality degradation, resulting in a lower fuel generation or a failure to supply pellets to the combustion chamber.
(2) Even if bamboo is stored for several days after cutting, it has a high moisture content of 70% or more, and it is expensive to dry to a moisture content of about 12% required in the pellet manufacturing process. Moreover, if mold adheres, the drying time has to be extended, and the drying cost becomes excessively high.

(3) For pellet fuel, it is an important quality control item that the amount of clinker generated when burned (domestic standard value of 1% or less) is an important quality control item. As a result, a large amount of clinker of about 1.5 to 5% is generated, and the burner in the combustion chamber is damaged by removing the clinker with a hammer or the like, or a heavy burden on the clinker removal is imposed on the pellet user.
(4) When pelletizing bamboo, the granulation energy in the granulation step (pelletizer) is 1.2 to 1.5 times greater than that of wood.

  The present inventor has found that almost 100% of the Si component is present in the branches and leaves of bamboo in response to the above problems (1) to (4) of bamboo, and as a raw material for bamboo pellet fuel, The inventors have found that the above-mentioned problems can be solved by mixing raw bamboo and dead bamboo, and mixing bamboo and wood, and have completed the present invention.

  The present invention uses a mixture of raw bamboo and withered bamboo as raw materials, or mixes these bamboos with raw materials as raw materials, thereby suppressing the fermentation of bamboo powder and preventing the generation of mold and improving the quality. It is an object of the present invention to provide a method for producing bamboo pellet fuel, in which high-calorie bamboo pellet fuel can be obtained, and at the same time, the production cost can be greatly reduced.

  In order to solve the above problems, the method for producing bamboo pellet fuel according to the present invention is based on 100% by weight of raw bamboo from which branches and leaves have been removed at 2 years of age or more, and the moisture content from which branches and leaves have been removed at least 2 years after birth. It was obtained in the crushing and crushing process, and the crushing and crushing process to obtain a mixed powder of bamboo base by mixing both in a crushing and crushing machine at a ratio of 25 to 400% by weight of dead bamboo less than 55% The first step is to have a drying step of drying the bamboo-based mixed powder with a dryer, and a granulating step of granulating the bamboo-based mixed powder dried in the drying step with a granulator to obtain bamboo pellets. Features.

  Here, the raw bamboo immediately after cutting has a moisture content of 70 to 80%, and a bamboo with a moisture content of 55% or more is referred to as a raw bamboo. A moisture content of less than 55% is called withered bamboo.

  According to the method for producing bamboo pellet fuel according to the present invention, in the crushing and crushing step, crushing and crushing are performed by mixing 25 to 400% by weight of dead bamboo having a moisture content of less than 55% with 100% by weight of raw bamboo. The later bamboo-based mixed powder can be adjusted to a low moisture content of 40% or less, which can suppress fermentation and prevent mold from adhering to the bamboo-based mixed powder and shorten the drying time. Can be lowered.

  Raw bamboo is harvested from bamboo forests such as 孟 宗 bamboo or bamboo hills for at least 2 years, preferably 4 years or more, transported directly to the collection site, removed foreign matter, rotten parts, leaves and leaves, crushed and crushed Into the machine. As for withered bamboo, raw bamboo harvested in bamboo forest is left locally or bamboo that is naturally withered in bamboo forest is used. The harvested raw bamboo is transported to the collection site when the water content is less than 55%, and foreign matters, rotting parts and branches and leaves are removed, and then put into a crushing and pulverizing machine. Withered bamboo, the weight of the bamboo is reduced by about 30 to 60% during transportation, and the transportation burden can be reduced.

  The resulting bamboo pellets generate more heat when burned than wood (specifically, about 4700-4800 calories in old bamboo over 4 years old, 4200-4600 calories in young bamboo 2 years-3 years old) By sealing the bag body, mold does not occur during storage and the quality can be maintained for a long time.

  Because the branches and leaves of raw bamboo and dead bamboo are removed before mixing, the occurrence of clinker is prevented, the burner in the combustion chamber is not damaged as before, and the burden of removing clinker is not imposed on pellet users. .

  In the method for producing bamboo pellet fuel according to the present invention, in the crushing and pulverizing step, 100% by weight of mixed bamboo of dead bamboo and dead bamboo is further mixed with 10 to 600% by weight of raw or dead wood having a water content of 75% or less. The second feature is to crush and grind.

  This suppresses fermentation inhibition and generation of mold and shortens the drying time, and at the same time, by adding wood powder, granulation energy (power consumption) in the granulation step (pelletizer) can be reduced. Thereby, the manufacturing cost can be further reduced.

  Here, a tree having a moisture content of 75% or less and 55% or more is referred to as a raw tree, a tree having a moisture content of less than 55% is referred to as a dead tree, and the dead tree preferably has a moisture content of 30% or more. In the case of a raw tree having a moisture content of 75%, the weight is set to 10% by weight with respect to 100% by weight of the mixed bamboo.

  In the method for producing bamboo pellet fuel according to the present invention, in the crushing and pulverization process, raw bamboo having a moisture content of 55% or more is obtained from raw bamboo cut from a bamboo forest or bamboo mountain, and a part of the raw bamboo cut is obtained for a certain period. A third feature is that a dead bamboo having a moisture content of less than 55% is obtained by leaving it to stand.

  Withered bamboo is obtained by leaving it in a local bamboo forest until the water content is less than 55%, so the weight of the bamboo is reduced by about 30-60% during transportation, reducing the transportation burden. In addition, it is possible to secure raw bamboo and dead bamboo from a bamboo forest in the same place at the same time, and it is possible to reduce the collection cost and consequently the manufacturing cost of bamboo pellets.

  The method for producing bamboo pellet fuel according to the present invention is characterized in that, in the drying step, the bamboo-based mixed powder is dried until the average moisture content becomes 10 ± 2%.

  A fifth feature of the method for producing bamboo pellet fuel according to the present invention is that it includes a moisture content adjusting step of adjusting the moisture content of the bamboo-based mixed powder between the crushing and pulverizing step and the drying step.

  By providing a moisture content adjusting step between the crushing and crushing step and the drying step, it is possible to cope with the case where the mixed powder of the bamboo base after the crushing and crushing step is overdried. That is, the moisture content of the bamboo-based mixed powder can be readjusted and sent to the drying process.

  As described above, according to the method for producing bamboo pellet fuel according to the present invention, bamboo with dead water mixed in a predetermined ratio and crushed and pulverized, and the moisture content greatly decreased through the pulverization and pulverization process. Since the base mixed powder is obtained and dried and granulated to obtain bamboo pellets, high quality bamboo pellet fuel can be obtained by suppressing fermentation and generation of mold, An excellent effect is achieved in that the drying time can be greatly shortened, whereby the drying cost can be greatly reduced, and the manufacturing cost can be greatly reduced.

  Further, it is possible to prevent the occurrence of clinker, and there is an excellent effect that burner damage in the combustion chamber in the drying process and a heavy burden on clinker removal are not imposed on the pellet user.

  The best mode for carrying out the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of the present invention, and FIG. 1 shows a manufacturing procedure of bamboo pellets according to the present invention.

(Bamboo logging and collection process)
A large number of raw bamboos (old bamboo) 2 that are 4 years old or older are cut down from bamboo forest 1, and the harvested raw bamboos 2 are transported to storage 3 and stored. The moisture content of the raw bamboo 2 immediately after cutting is usually 70 to 80%, and the raw bamboo 2 has a moisture content of 55% or more.

  A portion of the raw bamboo 2 that has been harvested from the bamboo forest 1 is left for a few days at the site to make a dead bamboo 4 with a moisture content of less than 55%. The raw bamboo 2 having a moisture content of 70 to 80% is reduced to a moisture content of 40 to 55% by leaving it for 20 days or more in a fine or cloudy condition. In addition, the withered bamboo 4 may cut and use the bamboo which naturally withered in the bamboo forest 1. Since the withered bamboo 4 after the moisture content has decreased is lighter than the fresh bamboo 2 (for example, the weight of the withered bamboo 4 with a moisture content of 30% is 46.6% of the weight of the raw bamboo 2 with a moisture content of 75%. It can be easily transported from the site to the collection place 3. The withered bamboo 4 transported to the collection place 3 is stored together with the raw bamboo 2.

  At the same time, a tree 5 is procured at the collection place 3. The wood 5 to be collected at the collection site 3 is made of thinned wood and offcuts generated in the lumbering process, and the moisture content is 75% or less and 30% or more.

(Crushing and crushing process)
The raw bamboo 2, dead bamboo 4 and tree 5 collected at the collection site are put together in the crushing / pulverizing machine 6 after the branches and leaves are removed, and are crushed and pulverized. The ratio of raw bamboo 2, dead bamboo 4 and wood 5 is 25 to 400% by weight with respect to 100% by weight of raw bamboo and 25% to 400% by weight of dead bamboo, and 100% by weight of mixed bamboo with dead bamboo. The rate is 10 to 600% by weight of raw or dead wood with a rate of 75% or less. If it is a raw tree with a moisture content of 75%, the ratio is 10% by weight with respect to 100% by weight of the mixed bamboo. If the moisture content is less than that, the mixing ratio of the tree is increased as the moisture content decreases. adjust

  The raw bamboo 2 and the dead bamboo 4 put into the crushing / pulverizing machine 6 are fibrillated by crushing and crushing to form fibrous bamboo powder. Moreover, the wood 5 thrown into the crushing / pulverizing machine 6 becomes wood powder by crushing and crushing. These bamboo powders and wood powders are mixed with each other in the crushing / pulverizing machine 6, the water content is lowered, and discharged as a bamboo-based mixed powder 7. The average moisture content of the discharged mixed powder 7 is 40% or less.

  When the screen size has a diameter of 8 mm, the fiber length of the bamboo powder is adjusted to 0.10 to 20 mm. Moreover, the length of the wood powder is adjusted to 0.10 to 20 mm.

  The mixed powder 7 discharged from the crushing / pulverizing machine 6 is passed through a sieve 8 and adjusted to a mixed powder 7 having a particle size of 0.10 to 5 mm.

(Moisture content adjustment process)
The average moisture content of the mixed powder 7 that has been passed through the sieve 8 and adjusted to a particle size of 0.10 to 5 mm is measured (according to JISZ 7303-3). In the case of overdrying with a moisture content of less than 8%, moisture is sprayed by the water sprayer 9 to adjust the average moisture content of the mixed powder 7 to 13% or more and 40% or less. Adjustment to 13% or more is because granulation is difficult if it is overdried, and adjustment to 40% or less takes time for drying, promotes fermentation, and may cause mold.

(Drying process)
The mixed powder 7 adjusted to an average moisture content of 13 to 40% is conveyed on a conveyor (not shown) to the charging port of the dryer 10, and is charged into the drying device 10 through the charging port. It is subjected to drying for a certain period of time. At this time, since the mixed powder 7 is adjusted to an average moisture content of 13 to 40%, it is possible to suppress the acceleration of fermentation and generation of mold, shorten the drying time, and reduce the drying cost (the fuel cost of heavy oil) Saving). The mixed powder 7 having an average moisture content of 13 to 40% is adjusted to an average moisture content of 10 ± 2% (= 8 to 12%) by the dryer 11.

(Containment process)
The mixed powder 7 discharged from the dryer 10 is conveyed on a conveyor (not shown) and is dropped and accommodated in the storage tank 11. In this way, a large amount of the mixed powder 7 adjusted to a moisture content of 10 ± 2% is accommodated and stored in the storage tank 11. Since the mixed powder 7 stored in the storage tank 11 is adjusted to a moisture content of 10 ± 2%, the promotion of fermentation and the generation of mold are also prevented here.

(Granulation process)
The mixed powder 7 quantitatively discharged from the storage tank 11 is quantitatively supplied to the granulator 12 side on a conveyor (not shown), and is introduced into the granulator 12 from the inlet of the granulator (pelletizer) 12. The mixed powder 7 put into the granulator 12 is forcibly pushed into a die hole of a forming die by an internal pressure roller (not shown).

  The mixed powder 7 pushed into the die hole passes through the die hole while being compressed, and is extruded from the die hole to be pelletized. The material extruded from the die hole during the pelletization process is cut into a predetermined size by a cutter, whereby a bamboo pellet fuel P made of a mixed powder of bamboo base is obtained. Since wood powder is added, the power consumption of the granulator 12 can be reduced.

  The water content of the obtained bamboo pellet fuel P is 5 ± 2%, and the size of the bamboo pellet fuel 16 is 5 to 25 mm in length and 5 to 8 mm in diameter.

(Inspection process)
The bamboo pellet fuel P obtained by the granulator 12 is inspected for diameter, length, moisture content, bulk density, and the like. The moisture content is measured with a moisture meter. Bamboo pellet fuel P that does not pass the inspection is removed from the line.

(Packing process)
The bamboo pellet fuel P that has passed the inspection is packed in a non-breathable bag after weighing. When storing for one year or longer, seal in a vacuumed state (10 mmHg or less) or insert a desiccant (silica gel or the like) and seal (1-2 kg / pellet 1000 kg).

(Transport and storage process)
The bamboo pellet fuel P packed in a bag is transported to a storage warehouse by a truck or a forklift and stored in a place and in a state free from the influence of moisture and direct sunlight. And it ships from a storage warehouse as needed.

  According to the present embodiment, it is possible to obtain bamboo pellet fuel P having excellent quality with no generation of mold. Also, the manufacturing cost can be greatly reduced to about 45% compared to the case of raw bamboo alone.

  Further, the raw bamboo 2, the dead bamboo 4 and the tree 5 are removed from each branch and leaf portion before being put into the crushing / pulverizing machine 6, so that the clinker is hardly generated. This prevents the combustion chamber burner from being damaged and imposes a heavy burden on the pellet user to remove the clinker.

  Power consumption (energy) in the granulation process can be reduced by 3 to 22% by mixing 10 to 90% by weight of raw or dead tree with 100% by weight of bamboo (raw and dead bamboo). Thereby, the manufacturing cost can be further reduced.

  Thus, according to the method for producing bamboo pellet fuel according to the present invention, while using raw bamboo with a high water content, by mixing dead bamboo at a predetermined ratio, the generation of mold is suppressed and high quality and high calorie bamboo is obtained. In addition to obtaining pellet fuel, it is possible to obtain bamboo pellet fuel with drastically reduced drying costs and greatly reduced manufacturing costs. Furthermore, by mixing wood at a predetermined ratio, it is possible to reduce the granulation cost and further reduce the manufacturing cost.

  In the above embodiment, the raw bamboo 2, the dead bamboo 4 and the tree 5 are fed to the crushing / pulverizing machine 6 at a predetermined ratio, but only the raw bamboo 2 and the dead bamboo 4 may be thrown at a predetermined ratio. .

As an example, the present inventor puts raw bamboo with a moisture content of 70%, withered bamboo with a moisture content of 35%, and wood with a moisture content of 55% into a crushing / pulverizing machine to obtain a mixed powder having a moisture content of 40% or less. At the same time, the mixed powder was put into a dryer and dried, and the dried mixed powder was granulated with a granulator to obtain bamboo pellets. The mixing ratio was 100% by weight with respect to 100% by weight of fresh bamboo and 60% by weight of wood (= 30% with respect to 100% by weight of mixed bamboo with dead and dead bamboo). The case where it consists only of raw bamboo with a moisture content of 70% was taken as a comparative example. Table 1 shows the results.

  According to Table 1, it was found that the drying energy was reduced by 68% and the granulation energy was also reduced by 8% in this example as compared with the comparative example. Further, the heat generated by the bamboo pellet fuel obtained in this example was 4700 kcal / kg. Furthermore, almost no clinker was observed.

  The method for producing bamboo pellet fuel according to the present invention can be used in various fields as a method for producing bamboo pellet fuel that has good quality and high calorific value while using raw bamboo with a high water content.

The figure which shows the manufacturing procedure of the bamboo pellet fuel of this invention, explanatory drawing which shows the procedure from the logging of bamboo in the bamboo forest to the collection place, The figure which shows the manufacturing procedure of the bamboo pellet fuel of this invention, explanatory drawing which shows the procedure to manufacture bamboo pellet fuel from collected raw bamboo, withered bamboo, wood, and to store, It is a graph which shows the moisture content of a pellet, and the generation | occurrence | production degree of mold.

1 Bamboo Forest 2 Raw Bamboo 3 Pick-up Area 4 Withered Bamboo 5 Trees
6 Crusher / Crusher 7 Mixed powder (Bamboo-based mixed powder)
8 Sieve 9 Water sprayer 10 Dryer 11 Storage tank 12 Granulator P Bamboo pellet fuel

Claims (5)

  Crushing and pulverizing both of them at a ratio of 25 to 400% by weight of dead bamboo with a moisture content of less than 55% from which branches and leaves were removed after 2 years of age, with respect to 100% by weight of raw bamboo from which branches and leaves were removed after 2 years of age Crushing and crushing by mixing and crushing and crushing to obtain bamboo-based mixed powder, drying step of drying bamboo-based mixed powder obtained in crushing and crushing step with dryer, and drying in drying step A method for producing a bamboo pellet fuel, comprising: granulating a bamboo-based mixed powder with a granulator to obtain bamboo pellets.   In the crushing and pulverizing step, the mixed bamboo of 100% by weight of raw bamboo and dead bamboo is further mixed with 10 to 600% by weight of raw or dead wood having a moisture content of 75% or less, and crushed and pulverized. Item 2. A method for producing bamboo pellet fuel according to Item 1.   In the crushing and crushing process, raw bamboo with a moisture content of 55% or more is obtained from raw bamboo harvested from a bamboo forest or bamboo mountain, and a portion of the raw bamboo that has been harvested is left for a certain period of time to produce dead bamboo with a moisture content of less than 55%. The method for producing bamboo pellet fuel according to claim 1 or 2, wherein the method is obtained.   The bamboo pellet fuel production according to any one of claims 1 to 3, wherein in the drying step, the bamboo-based mixed powder is dried until the average water content becomes 10 ± 2%. Method. 5. The moisture content adjusting step of adjusting the moisture content of the bamboo-based mixed powder is included between the crushing and pulverizing step and the drying step. 6. Bamboo pellet fuel manufacturing method.

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