液ホールドアップの特性に及ぼす充填層初期乾湿状態の影響(高炉内基礎現象および操業技術,高炉その1,<特集号>製銑プロセスの環境調和・資源対応力強化を目指して)

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In most previous works, liquid hold-ups were studied by using a cold model of a fixed bed soaked prior to experiments. However, they did not consider that the dripping zone of a blast furnace is saturated with liquids or with evenly distributed droplets. In the present study, the characteristics of liquid hold-ups and liquid flow were investigated by using a one-dimensional cold model of a fixed bed soaked and unsoaked prior to experiments (initially soaked and unsoaked beds). Packed balls were five kinds, the diameters (D_p) of which ranged from 5.4 to 30mm. Tap water was used as liquid. Contact angles (6) for these particle/liquid systems were about 70°and 10°for fluorine-coated particles and non-coated particles, respectively. Although, under bad wettability condition (θ≒70°), total and static hold-ups for initially unsoaked bed packed with small balls are remarkably smaller than those for initially soaked bed, the difference in their hold-ups between initially unsoaked and soaked beds decreases with increasing ball size in the bed. In initially soaked bed, total and static hold-ups increase monotonically as ball size decreases, which means the specific surface area increases. On the other hand, in initially unsoaked bed, total and static hold-ups under bad wettability condition indicate maximum values at about D_p=10mm and decrease abruptly in proportion to a decrease in particle size, despite an increase in the specific surface area. Only restricted liquid droplets and/or liquid rivulets are formed within the packed bed with good wettability condition (θ≒10°) for initially unsoaked bed, nevertheless liquid is easy to spread out on the solid surface. The influence of the initial bed condition, soaked or unsoaked bed, on liquid hold-ups is great under bad wettability condition.
2006-12-01

液ホールドアップの特性に及ぼす充填層初期乾湿状態の影響(高炉内基礎現象および操業技術,高炉その1,<特集号>製銑プロセスの環境調和・資源対応力強化を目指して)

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