화학공학소재연구정보센터
KAGAKU KOGAKU RONBUNSHU, Vol.45, No.2, 72-79, 2019
Evaluation of Dead-End Microfiltration Properties of O/W Emulsion Based on Centrifugal Flotation Data
To present a method for evaluating the properties of the filter cake deposited on the membrane surface in dead-end microfiltration of O/W emulsion, centrifugal flotation experiments of O/W emulsion were carried out using an analytical centrifuge that could monitor timed near-infrared (NIR) transmission profiles of emulsion in the centrifugal fields. Compression-permeability data representing the local specific cake resistance and local cake porosity as functions of solid compressive pressure were readily obtained by measuring the initial flotation velocities at various emulsion concentrations and the equilibrium thicknesses of the consolidated cream layers formed at various rotor speeds, in view of the analogy between the filtration mechanism and flotation mechanism of O/W emulsion. The average specific resistance and average porosity of the filter cake formed in dead-end microfiltration were evaluated from the compression-permeability data thus obtained, on the basis of the compressible cake filtration model that adequately takes into account the effect of the applied filtration pressure on the compressibility of the filter cake. To verify the validity of the pressure dependences of the average specific cake resistance and average cake porosity evaluated from the centrifugal flotation data, a method for evaluating the temporal flux decline behavior was applied not to the conventional down-ward dead-end microfiltration, in which the filter cake was partially scoured, but to upward dead-end microfiltration, from which the true properties of the filter cake could be obtained. As a result, it was found that the predicted flux decline behavior was in relatively good agreement with the experimental data. Thus, the determination of the compression-permeability data by the centrifugal flotation method may be available as a useful tool for accurately evaluating the microfiltration behavior of O/W emulsion.