Modeling of transient permeate flux decline during crossflow microfiltration of non-alcoholic beer with consideration of particle size distribution

Crossflow microfiltration of non-alcoholic beer is investigated numerically and it has been verified by experimental data. Due to the presence of particles with different sizes in feed suspension, a modified combination of three mechanisms of particle back-diffusion is developed to predict particle deposition and cake layer buildup during the process. The simulation results show that smaller particles (about 1 μm) are the main contributor to the cake layer due to a minimum in back transport and are the main reason of the flux decline. On the other hand, larger particles (ap > 20 μm) are swept away along the membrane during the filtration process and move toward the membrane exit due to the crossflow. Therefore, the cake enriches with finer particles as the permeate flux decreases. The specific cake resistance was determined experimentally and Carman–Kozeny equation fails to provide a complete theoretical perspective of specific resistance of irregular, non-uniformly sized particles that formed the cake layer. The results of numerical simulation are in good agreement with observed data.