Manabu Fuchihata

The Effect of Water Content Diameter on the Structure of Light Oil-Water Emulsion Spray Flame

Microexplosions of light oil-water emulsified fuel droplets were successfully documented using a high-speed video camera with laser illumination. The local frequency of the explosion occurrence, temperature profile and exhaust gas emissions were measured in spray flames of water-in-oil type emulsion formed using an air-assist atomizer with a ring pilot burner. Those results indicate that the flame structure changes as the water droplet diameter in the emulsion fuel was varied, even if the fuel components and their fractions were same. When the fuel includes the water droplet, whose median diameter was about 75μm, HC and CO emission were reduced as compared to those for the fuel of smaller water droplet content. It is probable that if the water droplet diameter is uniform, avalanching microexplosions occur at certain local region in the flame, and the water content vaporizes almost at once and extinguishes the flame. It leads to HC and CO emission increase. When the water droplet diameters are large, atomizer atomizes those; therefore, emulsion droplets include various size of water droplet in the flame. Consequently, the avalanching microexplosion occurrence is avoided, and HC and CO emissions are reduced.Copyright

Formation Characteristics of Bio-Coke Produced From Waste Agricultural Biomass

We aimed to effectively use unutilized rice straw by producing Bio-coke, which is a new briquette (in the rest of this document referred to as the BIC) with high density and hardness, from rice straw with various conditions based on initial water content and processing temperature and evaluated characteristics of rice straw BIC. First of all, the apparent density of BIC was calculated from its weight and volume, and the cold compressive strength for each BIC was measured. From the results, it showed that the relationship between apparent density and maximum compressive strength derived from the compression test had a positive correlation. Furthermore, the hot compressive strength of the BIC produced with 5% initial water content and 453K processing temperature was measured. The rice straw BIC had a maximum compressive strength of 4.8MPa at a high temperature of 973K. This hot maximum compressive strength is equal to about one third of the hot maximum compressive strength of coal coke, which is 12MPa. Also, it was determined that the maximum compressive strength of rice straw BIC is highest on both cold and hot compression tests, and BIC produced from agricultural biomass like rice straw and rice husk had higher maximum compressive strength at room and high temperatures than BIC produced from other materials. Thus, it seemed that fiber and silica contained in agricultural biomass helps maintain of structure of BIC.Copyright

Observation of Micro Premixed Flames Surrounded by High Temperature Burned Gas Flow

Flame structure of micro scale methane-air premixed flames is investigated experimentally. The flame is stabilized even on the burner whose diameter is 0.3 mm when it is with pilot flame. However, shape of the flame formed on the burner whose diameter is less than 1 mm is similar to micro diffusion flame. It is supposed that the flame formed on the burner whose diameter is submillimeter is dominated by the diffusion mixing of oxygen and methane from the premixture and heat and radicals from the pilot gas flow.Copyright

New Fuel BCDF (Bio-Carbonized-Densified-Fuel): The Effect of Semi-Carbonization

Publisher Summary Woody biomass is a potential energy resource for reducing greenhouse gas emissions. Two-third of the land area in Japan is covered with forest, but only a small amount of woody biomass is utilized for energy production. Therefore, it is necessary to reduce the labor and costs of gathering and transporting the materials to utilize it for energy production in Japan. This chapter explains how to improve the calorific density of woody biomass pellets, and reduce the transportation cost per unit energy. Increasing the energy density of bio-fuel is the most important requisite to improve its transportability. After the biomass is completely dried, it is dehydrated further by decomposition of cellulose, hemi-cellulose, and lignin, during carbonization. During dehydration, this process also occurs with the accompanying organic volatiles, and the energy yield of the carbonized wood is reduced. Therefore, semi-carbonizing conditions, at which maximum energy yield can be achieved, should exist. This chapter examines the optimum semi-carbonizing condition for pelletizing. In Japan, the amount of forest growth is big, which is estimated at 500Mdry-t/y. Nowadays, felling, collecting, and transportation are labor-intensive, hence, very expensive. Consequently, it is difficult for woody biomass to compete with fossil fuels in terms of price in Japan.