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Design and operation of unbaffled aerated agitated vessels with unsteadily forward–reverse rotating impellers handling viscous Newtonian liquids
Author(s) -
Yoshida Masanori,
Taguchi Yoji,
Yamagiwa Kazuaki,
Ohkawa Akira,
Abe Masahiko,
Tezura Shuichi,
Shimazaki Masuo
Publication year - 2003
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.813
Subject(s) - impeller , mechanics , sparging , aeration , newtonian fluid , power (physics) , materials science , non newtonian fluid , thermodynamics , control theory (sociology) , chemistry , mechanical engineering , physics , engineering , computer science , control (management) , organic chemistry , artificial intelligence
Design and operation of unbaffled aerated agitated vessels with multiple unsteadily forward–reverse rotating impellers (AJITERs) for viscous Newtonian liquids were studied. The effects of operating conditions such as gas sparging rate, agitation rate and the number of impeller stages, geometrical conditions such as the diameters of vessel and impeller, and the physical properties of liquids on the drag and added moment of inertia coefficients, necessary to predict the average and maximum power consumptions of the impellers in AJITERs, were evaluated and the empirical relationships which estimate values of each of these coefficients are presented. The effects of operating conditions, geometrical conditions and liquid physical properties on the gas hold‐up, ϕ gD , and volumetric oxygen transfer coefficient, k L a D , were evaluated in relation to the total power input which is the sum of the average power consumption of impellers, ie average agitation power input, and aeration power input. Empirical relationships, useful for design and operation of AJITERs, were obtained for each viscosity range, where the dependences of ϕ gD and k L a D on the specific total power input and superficial gas velocity differed, to predict ϕ gD and k L a D respectively as a function of the specific total power input, superficial gas velocity and liquid physical properties. © 2003 Society of Chemical Industry