Mass transfer intensification in the process of membrane cleaning using supercritical fluids

Abstract

Mechanisms of mass transfer intensification in the process of membrane cleaning using supercritical fluids were investigated. Transport properties, hydrodynamics of the solvent flow, mutual solubility of the solvent and the oil contaminant, and capillary effects occurring inside the porous membrane as factors affecting the overall process performance were studied. The analysis was performed using empirical correlations for the transport property coefficients and a model of the process implemented to CFD code developed using the OpenFOAM environment. Supercritical carbon dioxide exhibits favourable transport properties, which are highly tunable with process parameters and contribute to low mass transfer resistance. The investigated process is controlled by diffusive mass transfer inside the membrane pores, so increasing solvent flow rate has limited impact on the overall process rate. Mutual solubility of the oil and solvent phase leads to the effect of swelling of the oil phase, which promotes faster completion of cleaning. Capillary effects inside the pores may be another factor of process acceleration which requires further investigation.