PREDICTING STATIONARY PERMEATE FLUX IN THE ULTRAFILTRATION OF APPLE JUICE

Stationary permeate flux was studied in the hollow fibre ultrafiltrati on of apple juice The effect of flow velocity (Q = 10, 12.5 and 15 L/m in) and volume concentration ratio (VCR = 1, 1.5, 2 and 5) was determi ned over the 0-1.6 kg/cm(2) range of transmembrane pressure. The flux showed an asymptotic behaviour and proved to be pressure-independent a t a value that increased with Q and VCR. Flux also showed a hysteresis loop during the up and down curve with transmembrane pressure. Film t heory, surface renewal approach (SRM) and resistance-in-series model w ere used to analyse the experimental results. Fitting of experimental data to the Leveque laminar flow model was acceptable in the mass tran sfer-controlled region. Semi-empirical SRM concept appropriately descr ibes the entire pressure-flux behaviour observed during the ultrafiltr ation of apple juice. (C) 1996 Academic Press Limited