Plugging of hollow fiber lumen by a gel: Threshold operating conditions unraveled by simulations

Abstract

Membrane processes may experience gel plugs that require specific cleaning steps. This paper demonstrates with simulations how these plugs can occur. A physical model is used to describe the particular diffusive behavior of gels. This model is implemented in an OpenFOAM CFD simulation code to describe the dynamics of the gel layers when filtration is stopped. During this step of relaxation, it is shown that the gel can expand and lead to a plug with characteristic times in the order of minutes. The plugging is favored by a quick gel expansion and by a slow diffusion removal. The operating conditions leading to the gel plugging are analyzed and threshold conditions are unraveled. General practical recommendations on the process control are drawn from these results.