Enhancement of Gas–Liquid Mass Transfer with Unsteadily Forward–Reverse Rotating Multiple Delta Blade Impellers in an Unbaffled Agitated Vessel

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN

Masaki Minamoto²  Akira Ohkawa²  Shuichi Tezura¹  Kazuaki Yamagiwa²  Masanori Yoshida² 

[1] Shimazaki Mixing Equipment Co., Ltd.;Department of Chemistry and Chemical Engineering, Niigata University

关键词: Unbaffled Agitated Vessel;    Unsteadily Rotating Impeller;    Impeller Design;    Gas–Liquid Mass Transfer;    Behavior of Gas Bubbles;   

DOI  :  10.1252/jcej.07WE081

来源: Maruzen Company Ltd

【 摘 要 】

References(12)Cited-By(1)Gas–liquid mass transfer was studied experimentally for an air–water system in an unbaffled vessel with a liquid height-to-diameter ratio of 2:1 that was agitated by unsteadily forward-reverse rotating multiple impellers which alternated rotation direction. Two kinds of four-bladed impellers were used with different designs of triangular delta blades. One (S impeller) has a straight blade with a downward triangle apex throughout. The other (T impeller) has a twisted blade composed of an inner downward part and an outer upward part. With both the impellers, enhancement of the mass transfer was observed with increases in the liquid-phase mass transfer coefficient as well as the gas–liquid interfacial area that determine the magnitude of the volumetric coefficient characterizing the rate for water to absorb oxygen in air. The respective dependences of mass transfer parameters on the axial position within the vessel were evaluated for the mean bubble diameter and gas hold-up. T impeller produced a gas–liquid interface with a larger area and more uniform distribution than S impeller. The effect of forward-reverse agitation using the delta blade impellers on formation of the gas–liquid dispersion was confirmed in relation to the behavior of gas bubbles within the vessel.

【 授权许可】

Unknown