Flux improvement by Dean vortices: ultrafiltration of colloidal suspensions and macromolecular solutions

Coiled and straight hollow-fibre modules have been built and tested; the permeate flux obtained in ultrafiltration with these two geometries is compared for two feeds: a colloidal bentonite suspension and a dextran solution. In the case of colloidal suspensions, the secondary flows induced by the coiled geometry allow fouling to be reduced and the permeate flux is multiplied by a factor of up to 2. An empirical relationship is proposed to express the limiting flux of permeate as a function of both the velocity and some geometrical parameters of the coiled modules. Analogous results are obtained during the ultrafiltration of dextran. It is also shown that under certain conditions almost no deposit was formed; the permeate flux under these conditions is three times higher for coiled modules than for straight ones. For a given energy expenditure and ultrafiltration process, the gain in permeate flux can reach a factor of 1.8.

[1]  Georges Belfort,et al.  Fluid mechanics in membrane filtration: Recent developments☆ , 1989 .

[2]  L. Errede.  Effect of molecular adsorption on water permeability of microporous membranes , 1984 .

[3]  W. Edelstein,et al.  Dean vortices with wall flux in a curved channel membrane system.: 6. Two dimensional magnetic resonance imaging of the velocity field in a curved impermeable slit , 1993 .

[4]  T. Murase,et al.  Filtrate flux in crossflow microfiltration of dilute suspension forming a highly compressible fouling cake-layer , 1995 .

[5]  Robert H. Davis,et al.  The behavior of suspensions and macromolecular solutions in crossflow microfiltration , 1994 .

[6]  J. Dodds,et al.  Cake characteristics in crossflow and dead-end microfiltration , 1995 .

[7]  P. Aimar,et al.  Influence of surface interaction on transfer during colloid ultrafiltration , 1996 .

[8]  Christophe A. Serra,et al.  Mass transfer improvement by secondary flows: Dean vortices in coiled tubular membranes , 1996 .

[9]  Denis Roizard,et al.  Removal of volatile organic components (VOCs) from water by pervaporation: separation improvement by Dean vortices , 1998 .

[10]  L. Talbot,et al.  Flow in Curved Pipes , 1983 .

[11]  W. Edelstein,et al.  Dean vortices in curved tube flow: 5. 3‐D MRI and numerical analysis of the velocity field , 1993 .

[12]  W. R. Dean.  LXXII. The stream-line motion of fluid in a curved pipe (Second paper) , 1928 .

[13]  P. Mishra,et al.  Momentum Transfer in Curved Pipes. 2. Non-Newtonian Fluids , 1979 .

[14]  Georges Belfort,et al.  Dean vortices with wall flux in a curved channel membrane system , 1993 .

[15]  Georges Belfort,et al.  Enhanced performance for pressure-driven membrane processes: the argument for fluid instabilities , 1993 .

[16]  P. Aimar,et al.  Ultrafiltration of bentonite suspensions with hollow fiber membranes , 1992 .

[17]  J. Howell,et al.  Sub-critical flux operation of microfiltration , 1995 .