Hydrodynamic factors affecting flux and fouling during ultrafiltration of skimmed milk

Abstract

International audienceThe effects of independently varying both wall shear stress ($\tau_w$) and transmembrane pressure ($TMP$) on permeate flux and fouling during ultrafiltration of reconstituted skimmed milk in total recycle mode have been investigated. Irreversible fouling resistance ($R_{if}$) increased as $TMP$ increased. Increasing $\tau_w$ at constant $TMP$ led to an increase in both the initial flux, and subsequent flux decline, and to a decrease in $R_{if}$. At the highest $\tau_w$, increasing $TMP$ resulted in greater initial flux accompanied by increasing rates of flux decline and more irreversible fouling. Increasing and then decreasing $TMP$ in a controlled, stepwise manner at constant $\tau_w$ suggested that flux is governed by both a reversible, and an irreversible fouling layer which forms at higher $TMP$; this also controlled the transmission of protein. Critical operating conditions producing the least fouling were evaluated during this procedure

Critical and sustainable fluxes: Theory, experiments and applications

“…• lactalbumin : Howell et al [39] , Vyas et al [40] • Myoglobin : [22] • γ−lactoglobulim and IgG : [39] , Chan et al [41] • lysozyme : Chan et al [42] • Bovine Serum Albumine : [10] , [41] , [42] , Chen [43] , De Zarate et al [44] • Natural Organic Matter (NOM) or humic substances : [26] , Aoustin et al [45] , Seidel et al [46] , Yuan et al [47] • Emulsion : [8] Complex fluid • Yeast cells : [10] , [22] , [25] , Chang et al [48] , Sur et al [49] • Skimmed milk : [19] , Al Akoum et al [50] , Gesan-Guiziou et al [51] , Gesan-Guiziou et al [52] , Grandison et al [53] , Youravong et al [54] • Water and waste water : Chapman et al [55] , Choksuchart et al [56] , Vera et al [57] , Vera et al [58] • Lactic acid broth : [16] , [17] , Carrere et al [59] • Bioreactors sludge : Defrance et al [11] , [12] , Bouhabila et al [60] , Chang et al [61] , Cho et al [62] , Choo et al [63] , Fane et al [64] , Gander et al [65] , Jefferson et al …”

Principles of Membrane Filtration

“…Here, the ratio J/τ w defines the balance of particle deposition rate (relating to J ) and particle removal rate (relating to τ w ) and, therefore, determines particle transport towards the deposit layer (Altmann & Ripperger, 1997). If a critical value of J/τ w is exceeded, membrane processes become unsteady, thus operating conditions are recommended in which J/τ w is below that critical value (Le Berre & Daufin, 1996;Grandison et al ., 2000). This value varies with pore size, membrane material and feed composition, and needs to be determined experimentally for every membrane feed combination (Grandison et al ., 2000).…”

“…If a critical value of J/τ w is exceeded, membrane processes become unsteady, thus operating conditions are recommended in which J/τ w is below that critical value (Le Berre & Daufin, 1996;Grandison et al ., 2000). This value varies with pore size, membrane material and feed composition, and needs to be determined experimentally for every membrane feed combination (Grandison et al ., 2000).…”

“…2.12), but in other cases operating membrane filtration at the limiting flux causes more fouling and, therefore, reduces performance (Grandison et al ., 2000). This critical flux concept has lead to a subcritical membrane operation where the flux is initially kept below its critical value during operation start-up and only increased to the critical flux after cake layer establishment has taken place.…”

The effect of linear velocity and flux on performance of ceramic graded permeability membranes when processing skim milk at 50°C

“…The ratio defines the balance of particle deposition rate (relating to flux) and particle removal rate (relating to shear stress; Gesan-Guiziou et al, 2000). To achieve satisfactory MF performance (i.e., minimum fouling at high protein transmission), it is recommended to operate under conditions in which the ratio of flux to wall shear stress is lower than a critical value (Grandison et al, 2000). The objective of our research was to determine if increased linear velocity and retentate and permeate removal rates will increase the productivity (i.e., SP removal rate) without increasing fouling when processing skim milk with 0.1-μm Membralox GP membranes.…”