Numerical and experimental methodology for the development of a new membrane prototype intended to microfiltration bioprocesses. Application to milk filtration

In tangential flow filtration, the non-uniform TransMembrane Pressure (TMP) on the membrane length produces a non homogeneous filtration cake, initiates process selectivity changes and modifies the permeate quality. The purpose of this study is to create a tubular ceramic membrane prototype with a more uniform TMP, intended to filtration of fouling fluids. The principle of this membrane structure is to waterproof the external membrane surface to limit flow circulation in the porous support of the membrane. The production was controlled by sizing «permeation vents». This development was achieved using a CFD modelling tool interacting with experiments. A preliminary modelling study was made with water. This work was afterwards applied to the industrial process of casein micelle separation from skim milk. The influence of operating conditions on the membrane hydrodynamics was highlighted. The modelling results were experimentally confirmed, with a discrepancy smaller than 3% and a reproducible water permeability of 2.3 L h⁻¹ bar⁻¹ for 1 mm-wide vent (TMP = 1 bar, T = 20 °C). Then, milk filtration experiments showed a production ratio milk/water equal to 1/2. The permeate quality parameters were studied and the fouling phenomena were taken into account. A parametric study led to the sizing of a final prototype. Its efficiency was experimentally evaluated.