JP2022178280A - Bamboo charcoal molded body and manufacturing method of the same - Google Patents

Abstract

To provide a bamboo charcoal molded body and a manufacturing method of the same, wherein the bamboo charcoal molded body can be used as a fuel, has a high calorific value, and is excellent in usability.SOLUTION: A bamboo charcoal molded body can be used as a fuel, is mainly composed of a charcoal component containing bamboo charcoal powder and charcoal powder of a plant material other than bamboo, and contains 0.3 to 10 mass% of a plant sticky matter with respect to a charcoal component, the charcoal component contains the bamboo charcoal powder and the charcoal powder of the plant material other than bamboo in a mass ratio of (20:80) to (99:1), and the charcoal powder of the plant material other than bamboo is chaff smoked charcoal powder.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to a bamboo charcoal molded body obtained by molding bamboo charcoal powder into a pellet or the like, and a method for producing the same.

In recent years, biomass fuel has attracted attention as a carbon-neutral fuel. Biomass fuel is made from biologically derived organic resources (biomass). Although biomass fuel emits CO ₂ when burned, it absorbs CO ₂ during the growth process of the raw material crops, so the emissions are counted as virtually zero.

Generally, in biomass power generation using biomass fuel, securing stable raw materials is a major issue. For example, when wood is used as a biomass fuel, it is said that it takes 20 to 30 years to recover the felled forest, so it is necessary to constantly develop new sources of supply.

On the other hand, bamboo is known as a biomass fuel other than wood. Bamboo is a plant that grows vigorously, and since bamboo forests regenerate two to three years after being felled, there is no concern about depletion of raw materials, unlike wood. In recent years, neglected bamboo groves have also become a social problem due to the declining demand for bamboo and the aging of bamboo grove owners. Against this background, the reuse of bamboo is attracting attention, and attempts to use bamboo as a biomass fuel are underway. Bamboo charcoal, which is carbonized bamboo, is used as a biomass fuel because bamboo contains tar, clinker, and the like, and if it is burned as it is, it may damage turbines and boilers.

For example, Patent Document 1 proposes a biomass solid fuel obtained by kneading 70% to 95% by mass of sewage sludge with 5% to 30% by mass of bamboo charcoal powder. In Patent Document 1, by kneading sewage sludge with bamboo charcoal powder carbonized by a natural carbonization reduction method, a high calorific value (4000 cal/g or more) is obtained and ash content after combustion is reduced. It states that it is possible.

JP 2015-101721 A

The biomass solid fuel of Patent Document 1 is said to have a higher calorific value than general biomass fuels such as wood chips. However, since the biomass solid fuel contains a large amount of sewage sludge, there are concerns about the smell of sewage sludge and ease of handling.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a bamboo charcoal compact that can be used as a fuel, has a high calorific value, and is easy to use, and a method for producing the same.

The bamboo charcoal molded article of the present invention is a bamboo charcoal molded article that can be used as a fuel. It is characterized by containing 0.3% by mass to 10% by mass of sticky matter with respect to the carbon component.

The charcoal component is characterized by containing the bamboo charcoal powder and the charcoal powder of a plant material other than bamboo in a mass ratio of (20:80) to (99:1).

The charcoal powder of vegetable material other than bamboo is characterized by being rice husk charcoal powder.

The sticky vegetable matter is glutinous rice starch.

The method for producing the bamboo charcoal molded article of the present invention is a method for producing the bamboo charcoal molded article of the present invention, wherein the bamboo charcoal powder, the charcoal powder of a vegetable material other than bamboo, and the vegetable adhesive are mixed. Characterized by kneading and molding.

The bamboo charcoal powder is characterized by steaming and carbonizing bamboo at a firing temperature of 700°C to 1000°C.

The bamboo charcoal molded body of the present invention is mainly composed of a charcoal component containing bamboo charcoal powder and charcoal powder of a plant material other than bamboo, and contains 0.3% to 10% by mass of the vegetable sticky material based on the charcoal component. Therefore, it is lightweight and has excellent usability while having a high calorific value. In addition, since the vegetable sticky substance is glutinous rice starch, it is easily solidified, and the formability is excellent even though the charcoal component is the main component.

The method for producing the bamboo charcoal molded article of the present invention is a method for producing the bamboo charcoal molded article of the present invention, wherein the bamboo charcoal powder, the charcoal powder of a vegetable material other than bamboo, and the vegetable adhesive are kneaded. Since it is molded, it is possible to easily produce a bamboo charcoal molded body that is excellent in usability while having a high calorific value.

It is a figure which shows the SEM photograph and elemental-analysis result of bamboo charcoal. It is a figure which shows the SEM photograph and elemental-analysis result of rice husk charcoal. 4 is a graph showing changes in water temperature over time in a pellet combustion test. 4 is a photograph showing the appearance of a bamboo charcoal compact in a pellet combustion test. 4 is a photograph showing the appearance of rubber tree pellets in a pellet combustion test. It is a photograph which shows the state of the combustion test of a bamboo charcoal compact and Binchotan charcoal.

The bamboo charcoal molded body of the present invention is mainly composed of a charcoal component containing bamboo charcoal powder and a charcoal powder of a plant material other than bamboo, and contains 0.3% to 10% by mass of the vegetable sticky substance based on the charcoal component. is characterized by The bamboo charcoal molded body of the present invention can be used, for example, as biomass fuel for biomass power generation or fuel charcoal for charcoal grilling. The raw material for the bamboo charcoal molding and the like will be described in detail below.

(bamboo charcoal powder)
Bamboo charcoal powder is obtained by pulverizing bamboo charcoal obtained from raw material bamboo. Bamboo is a plant belonging to the subfamily Poaceae, Poaceae, which grows abundantly in Asia such as Japan, China, and Thailand, and many types are known. The type of bamboo used as a raw material is not particularly limited. , cold bamboo, and female bamboo of the genus Sasa can be used. One type or two or more types of bamboo can be used as a raw material.

Giant bamboo from Southeast Asia such as Thailand can also be used. This giant bamboo has few hollows inside and is a thick bamboo (about 30 mm to 50 mm thick). This giant bamboo has a short cultivation period of about 2 to 3 years compared to Japanese bamboo, and is excellent in securing stable raw materials.

Bamboo charcoal is obtained, for example, by steaming bamboo. The method of producing bamboo charcoal is not particularly limited, and for example, a method of arranging bamboo horizontally in a carbonization chamber of a charcoal kiln and then lighting a fire in a heating chamber located below the carbonization chamber (manufacturing method 1) can be adopted. In this method, the upper part of the carbonization chamber has a semi-closed structure and is formed in a dome shape or the like. A vent is provided in the heating chamber, and ventilation is controlled by opening and closing the vent. In addition, the charcoal kiln is equipped with a flue pipe that discharges the smoke produced by heating the bamboo. This smoke contains bamboo vinegar liquid such as tar and clinker, and water vapor. Bamboo vinegar is said to have deodorizing, sterilizing, and insect repelling effects, and refined bamboo vinegar is commercially available. On the other hand, in order to obtain good quality bamboo charcoal, it is necessary to efficiently discharge bamboo vinegar from the charcoal kiln.

In the present invention, in order to obtain bamboo charcoal of better quality, it is preferable to obtain bamboo charcoal by the following method (manufacturing method 2). In this method, the charcoal kiln has a carbonization chamber and a heating chamber located below it, and has a structure in which air is introduced from the upper part of the charcoal kiln and exhausted from the lower part. Specifically, the upper part of the carbonization chamber has a structure that allows outside air to enter, and the lower part of the heating chamber is connected to a flue pipe. By using such a charcoal kiln, an air current is generated from the top to the bottom, making it easier to discharge the bamboo vinegar contained in the bamboo from the charcoal kiln. As a result, bamboo charcoal of better quality, specifically, high-calorie and high-carbon bamboo charcoal can be obtained as compared with the production method 1 above.

Moreover, in the above manufacturing method 2, it is preferable to put the bamboo into the carbonization chamber after burning the fuel material in the heating chamber and lighting the fire in advance. The bamboo is then covered with a naturally breathable covering such as rice husks and steamed. As a result, outside air is introduced from the upper part of the carbonization chamber. If necessary, the rice husks may be further covered with coffee powder or the like. The firing temperature during carbonization is preferably 700° C. to 1000° C., for example.

By placing the bamboo in the carbonization chamber in a pre-heated state as in the above-mentioned production method 2, it is possible to reach the predetermined firing temperature as soon as possible from the start of firing, and the firing time can be shortened.

The bamboo charcoal obtained by the above manufacturing method 1 or manufacturing method 2 is pulverized into powder using a known pulverizer (for example, ball mill). The average particle size of the pulverized bamboo charcoal (bamboo charcoal powder) is not particularly limited, but is preferably 0.1 mm to 3 mm, more preferably 0.1 mm to 1 mm. When the average particle size is 1 mm or less, the bamboo charcoal compact can be more firmly solidified.

The pulverized bamboo charcoal may be sieved to a predetermined particle size using a standard sieve.

The bamboo charcoal powder used in the present invention may be the bamboo charcoal powder obtained by the method described above, or may be a commercially available product.

The bamboo charcoal powder used in the present invention preferably has a calorific value of 5000 cal/g or more, more preferably 6000 cal/g or more. For example, bamboo charcoal powder having a calorific value of 5000 cal/g or more can be obtained by carbonizing bamboo according to the production method 2 above. A particularly preferred range of calorific value is 7000 to 7800 cal/g. This calorific value can be calculated by the method described in Examples. The calorific value of wood pellets, which are general biomass fuels, is about 3000 to 4000 cal/g, and the calorific value of wood chips is about 2000 to 3000 cal/g. Thus, the bamboo charcoal compact can be burned with a high calorific value.

The bamboo charcoal powder used in the present invention preferably contains 60% to 80% by mass of fixed carbon, more preferably 70% to 80% by mass. Fixed carbon can be measured by a method according to ASTM D7582-15. Also, the ash content (according to ASTM D7582-15) is preferably 2% by mass to 5% by mass.

(Charcoal powder of vegetable material other than bamboo)
Wood, rice husks, coconut husks, diatomaceous earth, and the like are used as raw materials of plant origin. These can be used alone or in combination of two or more. In particular, as the charcoal powder of vegetable material other than bamboo, it is preferable to use rice husk charcoal powder obtained by carbonizing rice husks. When bamboo charcoal is produced by production method 2 described above, rice husks can be carbonized together with bamboo by using rice husks as a covering material, so that bamboo charcoal and rice husk charcoal can be efficiently obtained. In addition, as shown in Examples below, rice husk charcoal contains more silicon than bamboo charcoal. Since rice husk charcoal grows healthy roots, it is used as soil conditioner for seedlings, vegetables, fruits, and agriculture, and is easy to use.

As the charcoal powder of the plant material other than bamboo, the plant material as the raw material may be carbonized and pulverized by a well-known method, or a commercially available product may be used.

The grain average particle size of the charcoal powder of the plant material other than bamboo is not particularly limited, but it is preferably about the same as the average particle size of the bamboo charcoal powder because it is easy to mix with the bamboo charcoal powder. The average particle size is, for example, 0.1 mm to 5 mm. Moreover, you may use a well-known grinder etc. suitably.

The charcoal powder of plant material other than bamboo used in the present invention preferably has a calorific value of 2500 cal/g or more, more preferably 4000 cal/g or more. This calorific value can be calculated by the method described in Examples.

(vegetable slime)
As the vegetable sticky material, starches such as glutinous rice starch, sago starch, potato starch, corn starch, wheat starch, and sweet potato starch can be used. These can be used alone or in combination of two or more. These starches may be modified starches that have been chemically or physically processed. Processing treatments include, for example, acid treatment, esterification treatment, etherification treatment, cross-linking treatment, oil and fat treatment, and the like. The starch may be raw starch (β-starch), or, for example, α-starch obtained by preparing a starch paste by heating an aqueous suspension of raw starch and then drying it. .

Among the above starches, it is preferable to use glutinous rice starch. Glutinous rice starch is a starch produced from glutinous rice, which does not contain amylose and is composed only of amylopectin. Amylopectin is a sparingly water-soluble high-molecular-weight polysaccharide with a branched structure. By using glutinous rice starch, it is easily dispersed in the charcoal component, and as a result, it is easy to produce a firmly adhered bamboo charcoal compact. Glutinous rice starch is obtained, for example, by removing protein from glutinous rice as a raw material and extracting only the starch. A commercial product may be used as the glutinous rice starch.

Moreover, polysaccharides, such as gum arabic, can be used as a vegetable sticky substance other than the said starch.

The bamboo charcoal molded body of the present invention may be formed only from the above-mentioned bamboo charcoal powder, charcoal powder of a plant material other than bamboo, or a sticky plant material. Optional ingredients may be included.

In the bamboo charcoal compact of the present invention, a charcoal component containing bamboo charcoal powder and charcoal powder of a plant material other than bamboo is the main component. The content of the charcoal component is, for example, 60% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, relative to the bamboo charcoal compact.

Furthermore, in the bamboo charcoal molded body of the present invention, the charcoal component preferably contains bamboo charcoal powder and charcoal powder of a plant material other than bamboo in a mass ratio of (20:80) to (99:1). 80) to (80:20), more preferably (40:60) to (80:20). Since bamboo charcoal is easy to process, it can be easily formed into various shapes such as pellets by containing it to some extent.

In addition, the content of the vegetable sticky substance is 0.3% by mass to 10% by mass, preferably 0.3% by mass to 5% by mass, more preferably 0.3% by mass, relative to the carbon component. 3 mass %, more preferably 0.5 mass % to 3 mass %. The content of the vegetable sticky substance is appropriately set within each range depending on temperature, humidity, blending ratio of bamboo charcoal, intended use, and the like.

The production method of the present invention is a method of producing the bamboo charcoal molded body of the present invention described above, and kneads bamboo charcoal powder, charcoal powder of a plant material other than bamboo, and a vegetable sticky material to form a product. When molding into pellets, a well-known granulator or the like can be used. For example, in an extrusion-type granulator, pellets of a predetermined shape can be obtained by extruding a kneaded material through a large number of through holes formed in a wall member.

The shape of the bamboo charcoal molded body is appropriately set depending on the application. For example, in the case of a substantially cylindrical shape, the bamboo charcoal molded body can have a diameter of 6 mm to 40 mm and a length of 10 mm to 180 mm. Moreover, the specific gravity of the bamboo charcoal molded body is, for example, 0.10 to 0.20 g/cm ³ , preferably 0.10 to 0.15 g/cm ³ .

The bamboo charcoal molded body of the present invention can be used as biomass fuel for biomass power generation or as fuel charcoal for charcoal grilling. Biomass power generation is not limited to use in large-scale generators, but can also be used in small generators. Since the bamboo charcoal molded body of the present invention is lightweight, excessive work load is not applied even in fuel supply. Therefore, it can be suitably used, for example, as a biomass fuel for small power generators on private small-scale sites.

1. Calorie Analysis and Component Analysis Bamboo charcoal was obtained according to the production method 2 described above, using bamboo produced in Thailand as the raw material bamboo. As bamboo from Thailand, a thick bamboo (about 40 mm thick) and a thin bamboo (about 20 mm thick) were used. In production method 2, rice husks spread on bamboo were carbonized together with bamboo to obtain rice husk charcoal. The firing conditions were about 700° C. to 1000° C. for 48 hours. As the rice husks, domestically produced rice husks and Thai long-grain rice husks were used.

The calorific values of the obtained bamboo charcoal and rice husk charcoal were measured using an automatic cylinder calorimeter. In this measurement method, a weighed sample is completely burned in a cylinder into which oxygen is injected at high pressure. Asked for X _ALL . The calorific value X _s (unit: cal/g) of the sample was obtained by subtracting the calorific value of one sheet of Ganbi paper used in the calorimeter from the calorific value X _ALL . Specifically, it was calculated using the following formula (1). Table 1 shows the results.

As shown in Table 1, the calorific value of bamboo charcoal produced according to production method 2 was 7000 cal/g or more. Moreover, the calorific value of the rice husk charcoal was 2500 cal/g or more.

Next, SEM-EDX analysis was performed on the bamboo charcoal (Thai bamboo (thick)) and rice husk charcoal (produced in Thailand) shown in Table 1. SEM photography was performed using JSM-7100F (manufactured by JEOL Ltd.) at an accelerating voltage of 15 kV. The EDX analysis was performed on the captured image data using JED-2300 (manufactured by JEOL Ltd.) at an acceleration voltage of 15 kV and an irradiation current of 1 nA. The analysis results are shown in Table 2 and Figures 1-2. FIG. 1 shows the result of bamboo charcoal, and the magnification of the SEM photograph is 700 times. FIG. 2 shows the result of rice husk charcoal, and the magnification of the SEM photograph is 4500 times.

From Table 2 and FIGS. 1 and 2, it was found that the constituent atoms of bamboo charcoal are mainly carbon and oxygen, and the constituent atoms of rice husk charcoal are mainly carbon, oxygen and silicon. Silicon contained in rice husk charcoal is considered to be derived from silicic acid abundantly contained in rice husks.

2. Pellet combustion test <Example 1>
The bamboo charcoal (Thai bamboo (thick)) shown in Table 1 above was pulverized to obtain a bamboo charcoal powder. Also, the rice husk charcoal (produced in Thailand) shown in Table 1 above was pulverized to obtain rice husk charcoal powder.

A dispersion prepared by dissolving glutinous rice starch in 500 ml of water was added to bamboo charcoal powder and rice husk charcoal powder (mass ratio 50:50) and kneaded. This dispersion was added so that 0.3% by mass to 3% by mass of glutinous rice starch was contained with respect to the charcoal component. After kneading, the mixture was extruded and dried to obtain a cylindrical bamboo charcoal compact (pellet). The pellets (average) had a diameter of 7 mm, an axial length of 45 mm to 55 mm, a volume of 1.923 cm ³ , a specific gravity of 0.1287 g/cm ³ and a weight of 0.2475 g.

<Comparative Example 1>
Pellets made from rubber trees were used.

Using 500 g of the bamboo charcoal compact (pellets) and 500 g of the rubber tree pellets obtained above, 500 ml of water with a water temperature of 11°C is heated in an environment with an air temperature of 10°C to 12°C, and the temperature change in the water temperature is measured. did. The timing at which the pellet was ignited was taken as the start time (zero minutes). The pellets were ignited on a gas stove, and it took about 8 minutes to ignite the bamboo charcoal compact, and about 5 minutes to ignite the rubber wood pellets. The temperature change of water temperature is shown in the graph of FIG. In addition, FIG. 4 shows the state of the bamboo charcoal molding during combustion, and FIG. 5 shows the state of the rubber tree pellet during combustion.

As shown in FIG. 3, when the bamboo charcoal molded body was used, the water temperature rose rapidly, and the water was completely evaporated after 30 minutes from the start. The bamboo charcoal molded body continued to burn thereafter, and after 90 minutes from the start, the fire almost extinguished while maintaining the shape. In addition, almost no smoke or odor was generated during combustion.

On the other hand, rubber wood pellets showed a slower increase in water temperature than bamboo charcoal compacts. After 30 minutes from the start, the rubber wood pellets were mostly ash and the fire was extinguished, but water was still present. In addition, during combustion, a large amount of smoke was generated, and the smell and irritation to the eyes were strong.

3. Comparative combustion test with Bincho charcoal <Example 2>
A cylindrical bamboo charcoal molded body was obtained in the same manner as in Example 1 above. In this test, a bamboo charcoal molded body (briquette) having a size larger than that of the bamboo charcoal molded body of Example 1 was produced. The briquettes (average) had a diameter of 40 mm, an axial length of 180 mm, a volume of 226 cm ³ , a specific gravity of 0.8850 g/cm ³ and a weight of 200 g.

As shown in FIG. 6, the bamboo charcoal compact of Example 2 and binchotan charcoal of the same size were placed side by side on a charcoal brazier, and the state of combustion was observed. As a result, the bamboo charcoal compact of Example 2 burned for about 150 minutes without generating smoke or odor during combustion, like Bincho charcoal. The ignitability and fire retention were almost the same as Bincho charcoal. Since this bamboo charcoal compact can be produced at a lower cost than Binchotan charcoal, it can be used for charcoal grilling as an alternative to expensive Binchotan charcoal.

INDUSTRIAL APPLICABILITY The bamboo charcoal molded body of the present invention can be used as a fuel and has a high calorific value and is excellent in usability.

Claims (6)

A bamboo charcoal molded body that can be used as a fuel,
The bamboo charcoal molded body is mainly composed of a charcoal component containing bamboo charcoal powder and a charcoal powder of a plant material other than bamboo, and contains 0.3% to 10% by mass of the vegetable sticky material with respect to the charcoal component. A bamboo charcoal molded body characterized by: 2. The bamboo charcoal molded body according to claim 1, wherein the charcoal component contains the bamboo charcoal powder and the charcoal powder of a plant material other than bamboo in a mass ratio of (20:80) to (99:1). 3. The bamboo charcoal compact according to claim 1, wherein the charcoal powder of vegetable material other than bamboo is rice husk charcoal powder. 4. The bamboo charcoal molding according to any one of claims 1 to 3, wherein the vegetable sticky substance is glutinous rice starch. A method for producing a bamboo charcoal molded product according to any one of claims 1 to 4,
A method for producing a bamboo charcoal compact, characterized by kneading and molding the bamboo charcoal powder, the charcoal powder of a vegetable material other than bamboo, and the vegetable sticky material. 6. The method for producing a bamboo charcoal compact according to claim 5, wherein said bamboo charcoal powder is carbonized by steaming bamboo at a firing temperature of 700.degree. C. to 1000.degree.

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