M. Minier et al., STUDY OF THE FOULING EFFECT OF ANTIFOAM COMPOUNDS ON THE CROSS-FLOW FILTRATION OF YEAST SUSPENSIONS, Separation science and technology, 30(5), 1995, pp. 731-750
The fouling effect of different antifoams and compounds of antifoams o
n crossflow filtration membranes is studied by on-line measurement of
the permeation flow during the concentration of suspensions of baker's
yeasts in reverse osmosis water (initial yeast concentration, 9 g/L d
ry matter; concentration factor, 6). The experiments are carried out o
n three types of tubular mineral microfiltration membranes, two types
of flat-sheet organic microfiltration membranes, and one ultrafiltrati
on mineral membrane. The compounds tested are principally silicone oil
s, silica + silicone based antifoams, and a modified organic antifoam
(modified polyalcoxyester). The presence of 100 ppm of any of these co
mpounds in the initial feed suspension does not cause a measurable eff
ect for all membranes compared to the fouling due to yeasts. The fouli
ng of a microfiltration mineral membrane due to the amount of silicone
antifoam equivalent to 2 years of industrial operation (that is, cumu
lated in one run without yeast, 25,000 ppm in 12 L feed solution) does
not increase beyond the fouling resulting from filtration of the refe
rence yeast suspension.