Our study has object to inspect the usefulness of gross energy estimated by feed composition analysis procedure in animal husbandry, estimating easily and accurately calorific value of biomass. Fifteen kinds of biomass materials from plants, food industrial wastes, and compost from cattle wastes were analyzed to determine their component organic compounds (protein, fat, fiber and nitrogen-free extract) through ingredient analysis, and also their elemental composition (hydrogen, carbon, oxygen, and nitrogen) through elemental analysis. The actual calorific values of each material, measured by the bomb calorimeter, were compared to the estimated calorific values that were calculated from the unit calorific value of each organic element, or from the chemical elements using Dulong's formula, wherein results revealed that the former estimation method resembles the actual measurement with higher accuracy than the later.
People in the world have been eating rice for a long period of time, especially in Asian countries including Japan that considers rice as its staple food. Like many agricultural products, agricultural waste like rice husk and rice straw are a big disposal problem. One of the solutions for this problem is solidification. It is better to use the solid as fuel for heating and create a cycle of local production for local consumption. In this study, we established formation temperature and particle size as parameters and produced solid fuel (hereinafter referred to as BIC) from rice husk with high-density and high-hardness solidification technology. The apparent density from weight and volume of BIC and assessed compressive strength of BIC with compression test under room and high temperature was calculated. From derived results physical and mechanical properties were considered. Results showed that rice husk of small particle size had better lignin reaction than large one. However, it is also revealed that the maximum compressive strength at room and high temperature was both weak in the case of crushing the particle size of the rice husk too small.
In recent years, the development of bio-energy in cooperation with an ASEAN country is a very important issue for both participating countries, which would be able to build a win-win relationship. ASEAN countries have a large amount of unused biomass resources. However, raw biomass business does not seem to work well based on experience unless a new technology is introduced. The Bio-coke (referred to as BIC) is a domestic energy technology in Japan. In this study, Bio-coke made from unused resources of fruits that are imported in large quantities from ASEAN countries is being focused. The compressive strength measured for Banana peel Bio-coke was 98.4 MPa at initial moisture of 1.81 mass% while the Orange peel Bio-coke measured 167.0 MPa at initial moisture of 0.52 mass%. Meanwhile, the apparent Yang's modulus ratio based on cool compressive test for the former is about 4.0 GPa and 4.5GPa for the latter. Through hot compressive test at 973 K, 8 MPa was recorded for Banana peel Bio-coke and about 4.2 MPa for Orange peel Bio-coke.
Currently, various energies such as fossil fuels and nuclear power are considerable expenditures. Resource depletion and environmental issues are taking place by activation of various problems and economic activity due to population growth in developing countries. However, in order for society to develop, energy, such as natural energy, is required have been studied for this purpose. A variety of energy including conventional type energy is needed. In this study, using Bio-coke that has attracted attention as a natural energy, a research was conducted using rice bran, which is an unused biomass in Thailand. By adding rice bran to 2-mm pulverized wood waste materials in making Bio-coke, it was found that Bio-coke density increased proportionally with increase in rice bran ratio. Results also showed that by adding rice bran in the raw material, it is possible to simultaneously improve both the gross calorific value and cold compressive strength. Moreover, reduction in environmental impact is also possible in the production process by optimizing the production conditions.
A high frequency induction furnace is batch-type, and it is fit for limited production with a wide variation, and it is a type of equipment introduced in many foundries at present. By the addition of Biocoke(referred to as BIC) in producing cast iron in previous studies, it has been found that carburizing effect can be obtained in the cast iron. However, many questions arise like the actual carburizing amount affected by the different types of biomass that can be used as carburization material substitute in induction melting furnaces since there have been no previous records regarding this. In this experiment, the carburization effect on iron casting using BIC made from a mass ratio mixture of 80mass% wood (stem:bark = 5 : 5) and 20mass% of bamboo as a substitute carburizing material. Moreover, regarding the dissolution of electric power consumption rate by addition, the effects on the mechanical properties of cast iron were examined. As a result, it turned out that the substitution of carburization material with 20mass% BIC has no influence on the chemical constitution of the cast iron, its mechanical properties, and also metallographic structure. There is also no difference in dissolution time and dissolution speed. With these conditions, it is thought that 20mass% mass substitution of the carburization material in a high frequency induction fusion melting furnace is possible and leads to effective use of BIC manufactured from unutilized biomass. Furthermore, these results could lead to streamlining of the carburization material and it can contribute to reduced dependence on fossil fuel and thereby also contributing to cost reduction.
Recently, biomasses attract much attention as a renewable energy resource. Biocoke, hereinafter called BIC, is one of the solid biomass fuels that are made from woody or herbaceous biomass by heat and compression processes. BIC is highly dense, has high hardness, has a high energy density, and is expected to be an alternative to coal coke. In the present study, the carbonization and combustion properties of a green tea BIC and a cypress BIC are experimentally examined. The experimental results show that the carbon residue of the BICs is higher than that of raw wood in spite being of the same material. Further, the weight reduction curve during the combustion process of the BIC carbide is similar to that of charcoal when the carbonization temperature is higher than 673 K. Consequently, it is considered that the BIC can maintain adequate hardness even if it is carbonized at the upper portion of a cupola furnace, and burns as an alternative to coal coke in the coke bed at the bottom of the cupola furnace.
The high density high hardness solid fuel (bio-coke) developed by Ida et al. is being hoped for as a solid fuel for heating machineries such as a heavy oil farm boiler. The diameter of the bio-coke made in high pressure and high temperature has a range of 8mm to 100mm. In the case of the 100mm diameter bio-coke specimen, neither pressure nor the temperature is uniform because of thermal conductivity of the biomass and the friction against the cylinder wall. With these reasons, the qualities of the inside of the specimen do not become uniform. Through X-ray CT, nondestructive measurement of the spatial distribution of the x-ray absorption coefficient in the specimen can be done. The x-ray absorption coefficient changes depending on the density of the material, hence, the applicability of this procedure to estimate the X-ray CT quality distribution of a large bio-coke was examined. Results showed that the CT values obtained through X-ray CT have strong relationships with the density distribution in the specimen. Moreover, the CT values were confirmed to be able to effectively estimate the quality distribution of the inside of a large bio-coke.
To supply good quality domestic woods for house construction steadily, it is necessary to promote installation of wood drying system. In the case of kiln drying equipment, the energy consumption of drying becomes extremely high, while the drying period is short. To mitigate the global warming due to the exhaustion of CO2 from fossil fuels, the passive solar system for wood drying in an agricultural green house has been experimentally investigated. The installation cost of green house is low, but the following two points have to be improved to make the solar drying system for practical use: (1) the promotion of drying rate at nighttime, (2) the reduction of cracks appearing in wood with dry shrinkage at daytime. In the present study, the placement of phase change materials (PCM) in green house is proposed, and effects of PCM on air temperature rise at nighttime and drying rate are examined. The following results are obtained. (1) The air temperature in green house at nighttime increases due to the heat storage of PCM at daytime. The heat transfer between the air and PCM board in green house is affected by the arrangement of PCM board, and it is found that the vertical arrangement induces the improvement of heat transfer, which increases the heat storage of PCM and air temperature at nighttime. (2) In the constant drying rate period, the placement of PCM causes the decrease in the drying rate due to the decrease in the highest air temperature at daytime. In the falling drying rate period, the drying rate is increased by the increase in the air temperature at nighttime due to the heat storage of PCM.
A greenhouse with latent heat storage boards is proposed as a passive solar system for drying of woody biomass. From the results of wood drying experiments in greenhouse, it is confirmed that the latent heat storage boards are effective in keeping the greenhouse warm at nighttime, which improves drying rates in the falling drying rate period. However, in autumn and winter seasons, the melting point of phase change material (PCM) in the latent heat storage board has to be reduced, because the air temperature in greenhouse is too low to melt the phase change material. The amount of heat storage for low melting point PCM is about one-half that for high melting point PCM. In the present study, to utilize the high melting point PCM in autumn and winter seasons, both effects of improvement of heat transfer coefficient of latent heat storage board and insulation of greenhouse wall on the temperature rise at nighttime are investigated by numerical simulation. Results showed that in autumn, the high melting point PCM can be utilized by circulating the air in the greenhouse or installing the insulation walls. In winter, the high melting point PCM can be utilized by both improvements of heat-transfer coefficient and thermal insulation walls.
Rice husks, one of the typical agricultural wastes, consist with 70-75 mass% of organics and 15-20 mass% of amorphous silica. Silica can be obtained by combusting rice husks in air. However, silica purity is reduced by metallic impurities contained in rice husks. To extract high-purity amorphous silica from rice husks, the citric acid leaching process was developed to remove the metallic impurities from rice husks. By optimizing the citric acid solution concentration and combustion temperature of rice husks, completely amorphous silica ashes with 99.5 mass% were obtained. To establish the large-scale equipment to produce high purity amorphous rice husk silica, the process parameters in the citric acid leaching and air combustion were optimized. There was no significant difference of silica purity and the impurity contents of rice husk ashes by using between small-scale and large-scale equipment. Citric acid leached rice husk ashes were employed as the reinforcements of concrete materials. Compressive strength in use of high-purity amorphous silica revealed a higher value compared to the use of silica fume and raw rice husk ashes. The effect of citric acid leached rice husk ashes was high pozzolanic reactivity due to high-purity amorphous silica particles and the large surface area due to their porous structures.
A new type of circulating fluidized bed gasifier, which is called a fluidized bed gasifier with triple-beds and dual circulation, was proposed. Main features are the adoption of a triple-beds structure, the separation of circulation paths for tar-absorbing particle and fuel. Pyrolyzer and gasifier each have a two-stage fluidized bed. Tar can be processed in the gasifier. The two circulation systems each have an independent combustor. The purpose of this study is to evaluate the gasification characteristics of woody biomass by bed material in a fluidized bed gasifier. The bed material used porous alumina and limestone. As a result, the reforming of tar of porous alumina is much higher than that of limestone. Therefore, the porous alumina, which can process the tar in a fluidized bed gasifier, is suitable for the bed material. Additionally, the amount of tar absorbed by porous alumina was elucidated by the gasification experiment through which particles circulate continuously. The tar was generated because the fuel was supplied on the porous alumina particle bed. It is predicted that the amount of tar absorbed by porous alumina is more improved in a practical gasifier because the contact efficiency between the porous alumina and the tar in the proposed gasifier is much higher than that of this experimental condition.