| Co-Investigator(Kenkyū-buntansha) |
小屋 敏行 東京大学, 工学部, 教務職員 (60090510)
MINEO Hideaki University of Tokyo, 工学部, 助手 (90209841)
TSUTSUMI Atsushi University of Tokyo, 工学部, 助手 (00188591)
YAMAZAKI Ryohei University of Tokyo, 工学部, 助教授 (10023277)
KOYA Toshiyuki University of Tokyo
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| Budget Amount *help |
¥8,700,000 (Direct Cost: ¥8,700,000)
Fiscal Year 1988: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1987: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1986: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Research Abstract |
The objective of this project is to develop a combined process for direct reduction of fine iron ore by using mixture of fine iron and char particles in a fast fluidized bed.
For this purpose, experiments were carried out both on the behavior of gas and solid particles, and on the reduction of iron ore by char gasification. The following following results were obtained.
(1) Flow behavior of gas and solid particles and mixing characteristics of the two components particle system in a fast fluidized bed
Mesurements of the local solid particle velocity showed that the bed could be divided into two regions, i.e., a core region in which particles ascended and an annular region in which particles descended. On the other hand, the local gas velocity could be described with the distribution function which was obtained by applying Prandtl's 7th root law the particle-ascending region. in addition, the measurement of spatial distribution of local solid holdup revealed that the distributions above a
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gas velocity of 2.0m/s were similar, and that the holdup averaged over the bed cross-section decreased exponentially with the bed height.
Concerning the mixing characteristics of two species of particles with different sizes and/or densities, a dense bed of coarse particles in the bed bottom was observed at a relatively low solid rate. When the solid rate was further increased, however, the profile of weight fraction of coarse particles throughout the bed height was relatively uniform, implying that coarse particles had little tendency of segregation, even though gas velocity was smaller than the terminal velocity of a coarse particle.
(2) Characteristics of iron reduction in a fast fluidized bed
The experiments were conducted on the iron reduction using the powder mixture of iron ore and char particles in a fast fluidized bed. Chemical analysis of gas and solid particles showed that iron ore was completely reduced by hydrogen and carbon monoxide, forming Wustite(FeO) within 45 minutes.
During reduction, the bed was also found to be kept at stable fast fluidizing state. In addition, the use of a coarse char particle was more promising than a fine char particle to obtain high concentration of reducing gas.
To provide a basis for both the system design and the development of direct irom-ore reduction process, many fundamental aspcts were clarified. Less
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