Predicting stationary permeate flux in the ultrafiltration of apple juice

Abstract

Stationary permeate flux was studied in the hollow fibre ultrafiltration of apple juice. The effect of flow velocity (Q =10, 12.5 and 15 L/min) and volume concentration ratio (VCR =1, 1.5, 2 and 5) was determined over the 0-1.6 kg/cm2 range of transmembrane pressure. The flux showed an asymptotic behaviour and proved to be pressure-independent at a value that increased with Q and VCR. Flux also showed a hysteresis loop during the up and down curve with transmembrane pressure. Film theory, surface renewal approach (SRM) and resistance-in-series model were used to analyse the experimental results. Fitting of experimental data to the Leveque laminar flow model was acceptable in the mass transfer-controlled region. Semi-empirical SRM concept appropriately describes the entire pressure-flux behaviour observed during the ultrafiltration of apple juice. ©1996 Academic Press Limited.