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Solid–liquid mass transfer characteristics of an unbaffled agitated vessel with an unsteadily forward–reverse rotating impeller
Author(s) -
Tezura Shuichi,
Kimura Akihiro,
Yoshida Masanori,
Yamagiwa Kazuaki,
Ohkawa Akira
Publication year - 2008
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.1849
Subject(s) - impeller , mass transfer , mixing (physics) , rotation (mathematics) , mechanics , materials science , mass transfer coefficient , turbine , aeration , slip factor , mechanical engineering , chemistry , physics , engineering , geometry , mathematics , organic chemistry , quantum mechanics
To develop an enhanced form of solid‐liquid apparatus, an unbaffled agitated vessel has been constructed, fitted with an agitation system using an impeller whose rotation alternates unsteadily in direction, i.e. a forward‐reverse rotating impeller. In this vessel, solid‐liquid mass transfer was studied using a disc turbine impeller with six flat blades. The effect of impeller rotation rate as an operating variable on the mass transfer coefficient was evaluated experimentally using various geometrical conditions of the apparatus, such as impeller diameter and height, in relation to the impeller power consumption. Mixing of gas above the free surface into the bulk liquid, i.e. surface aeration, which accompanied the solid‐liquid agitation, was also investigated. Comparison of the mass transfer characteristics between this type of vessel and a baffled vessel with a unidirectional rotating impeller underscored the sufficient solid‐liquid contact for prevention of gas mixing in the forward‐reverse rotation mode of the impeller. Copyright © 2008 Society of Chemical Industry