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Hydrodynamic and mass transfer characteristics of bubble and packed bubble columns with downcomer
Author(s) -
Gopal J. S.,
Sharma M. M.
Publication year - 1982
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450600305
Subject(s) - bubble , mass transfer , pressure drop , packed bed , contactor , mass transfer coefficient , materials science , surface tension , drop (telecommunication) , analytical chemistry (journal) , thermodynamics , maximum bubble pressure method , mechanics , chemistry , chromatography , physics , telecommunications , power (physics) , computer science
The hydrodynamic and mass transfer characteristics of bubble and packed bubble columns with downcomer were investigated. The contactor consisted of two concentric columns of 0.11 and 0.2 m i.d., with the annulus acting as the downcomer. The packing used in this investigation was standard 16 mm stainless steel Pall rings. The superficial gas and liquid velocities, V G and V L , were varied from 0.01 to 0.09 and 1 × 10 −3 to 8.8 × 10 −3 m s −1 respectively. Two flow patterns, namely the bubble and pulse flows were observed in the packed bubble column with downcomer, as shown by a flow map. The liquid circulation velocity in both the contactors was observed to be constant throughout the ranges of V G and V L covered in this work. The effect of liquid viscosity (0.8 to 9.5 mPa ṁ s) and surface tension (45 to 72 mN m −1 ) on the flow pattern, liquid circulation, gas hold‐up and pressure drop was investigated. The pressure drop characteristics across the two contactors have been compared with those across a bubble column. Values of the effective interfacial area, a, and the volumetric mass transfer coefficient, k L a, were measured by using chemical methods. Values of a as high as 180 and 700 m −1 and k L a as high as 0.075 and 0.22 s −1 , in the bubble and packed bubble columns with downcomer, respectively, were obtained. The values of true liquid‐side mass transfer coefficient, k L , were found to be independent of V G and were of the order of 5.5 × 10 −4 and 3.5 × 10 −4 m s −1 , respectively, in the two contactors.