Analysis of Mass Transfer in Beer Diafiltration with Cellulose-Based and Polysulfone Membranes

An experimental investigation of beer dialysis with transmembrane pressure (diafiltration) was performed using two different hollow-fibre membranes: cuprophane (regenerated cellulose) and polysulfone for different flow rates and transmembrane pressure differences (TMP). In this process two simultaneous mass transfer mechanisms take place—diffusion and convection. On the basis of the experimentally measured inlet and outlet concentrations, the diffusive and convective components of the alcohol and extract fluxes were determined. It was found that the contribution of convective transport introduced by the TMP depends on the membrane type, beer flow rate and solute molecule size. The diffusive component is of primary importance for the elimination of alcohol molecules, while the convective component plays an important role in the transport of large molecules and extract loss.