Improvement of the performance of the ultrafiltration of bentonite suspensions using a swirling decaying annular flow: comparison with tangential plane and axial annular flows
O. Morineau-thomas et al., Improvement of the performance of the ultrafiltration of bentonite suspensions using a swirling decaying annular flow: comparison with tangential plane and axial annular flows, J MEMBR SCI, 193(1), 2001, pp. 19-33
The limiting flux induces a performance limitation of ultrafiltration syste
ms, the understanding of this phenomenon and the ability to predict the lim
iting flux are essential for improving the design and operation of ultrafil
tration processes. A new cell design, an annular cell fitted with a tangent
ial inlet, which induces a swirling decaying flow, is tested. Performances
of this ultrafiltration unit configuration are compared with two other more
classical geometries: a simple plane unit and an annular cell involving ma
inly axial flow. The cross-flow ultrafiltration of dilute suspensions of be
ntonite is studied under specific operating conditions in the three differe
nt configurations of filtration cells. The improvement of the permeation fl
ux in the swirling cell, compared with that measured in the two other confi
gurations, can reach 70% for a wall velocity gradient of 800 s(-1). This en
hancement is highly linked to the removal of particles deposited at the mem
brane surface owing to the three-dimensional fluid flow involved in this pa
rticular cell. The bentonite deposit is compressible and characteristics of
particles accumulation at the membrane surface are investigated. (C) 2001
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