<報文>酸化鉄ペレットの水素還元におけるガス側物質移動係数の評価

概要

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The mass transfer coefficient surrounding the iron oxide pellet in the gaseous reduction under a low flow rate of reducing gas was examined. It has been reported qualitatively by other researchers that the overall reduction rate was influenced by the product gas of reaction. However, its effect has not been evaluated quantitatively. In this paper, in order to obtain a useful information on the quantitative evaluation of the effect, the reduction rates of iron oxide pellet with hydrogen were measured under various flow rates of reducing gas and different flowing conditions of the gas. Two different experimental methods were used for the flowing conditions of the gas. That is, the reduction of a single pellet in the empty tube and in the packed bed composed of alumina balls. By applying the rate equation derived on the basis of the unreacted core model to the experimental reduction curves, the mass transfer coefficient through gaseous phase were evaluated. The mass transfer coefficient surrounding the pellet can be expressed by the following empirical equations : Sh=0.12 (Re_p)^<1.79> (Sc=0.35,0.5<Re_p<5) for empty tube ; Sh=0.27 (Re_p)^<1.79> (Sc=0.35,0.5<Re_p<3) for packed bed. The calculated reduction curves obtained by these empirical equations agreed well with observed ones.
東北大学の論文
1975-03-25