Application of Combined Cake Filtration-Intermediate Blocking Model and Intermediate-Standard Blocking Model to Ultrafiltration of Skim Milk

Major drawback in application of ultrafiltration membrane processes is fouling, a complex phenomenon which highly depends on the operational conditions such as pH, temperature, feed velocity, trans-membrane pressure and the geometry of the membrane unit. Milk fouling mostly arises from precipitation of proteins and fats in the form of a cake layer on the surface of the membrane. In this study, combined cake filtration-intermediate blocking model and combined intermediate-standard blocking model were applied to ultrafiltration of skim milk at constant flow rate. The effect of trans-membrane pressure and temperature on flux decline was investigated. Based on the results obtained here, the combined intermediate blocking and standard blocking model provided the best simulation, as it was able to fit the experimental data for skim milk concentration with low error values. With increasing pressure to 100 kPa, the differences between combined cake formation-intermediate blocking model and experimental data increased and with further increase in the pressure the differences decreased.