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Gas‐Liquid Mass Transfer in Pulp Retention Towers
Author(s) -
Rewatkar Vilas B.,
Bennington Chad P. J.
Publication year - 2004
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.5450820306
Subject(s) - mass transfer , superficial velocity , mass transfer coefficient , chemistry , chromatography , analytical chemistry (journal) , nitrogen , kraft process , pulp (tooth) , kraft paper , bubble , suspension (topology) , materials science , composite material , mechanics , flow (mathematics) , medicine , physics , mathematics , organic chemistry , pathology , homotopy , pure mathematics
The volumetric gas‐liquid mass transfer rate, k L a , was measured under batch conditions in a 0.28 m diameter laboratory‐scale retention column. Tests on water, and on unbleached kraft (UBK) pulp suspensions (mass fractions, C m from 0.013 to 0.09) were made with air or nitrogen sparged through the column at superficial gas velocities between 0.0015 to 0.05 m/s. k L a varied with suspension mass concentration and superficial gas velocity, initially decreasing with increasing mass concentration, reaching a minimum between C m = 0.03 and 0.06, and then increasing. The minimum in k L a coincided with a change in hydrodynamics within the column, from bubble column behaviour below C m = 0.03 to porous solid behaviour above C m = 0.06.