ABSTRACT

The Institut Français du Pétrole has implemented a refinery process, which consists in injecting a gas across a catalyst moving bed. It involves a complex medium: a mix of granular material with a flowing gas inside. Our present concern is about phenomena appearing inside the refinery reactor when a horizontal gas flow goes through a vertically moving granular bed. As the pressure drop is increased between the extremities of the granular bed, some disturbances appear in the regular vertical motion of the grains. The catalyst bed can cavitate (cavitation) or even stop moving (pinning effect). Thanks to image analysis applied to experimental equipment, a criterion, based upon the kinematics of the grains, is used to characterize the phenomena: the cavitation and the pinning. The results are then compared to analytical estimation of the cavitation. A numerical approach using the finite element method is proposed.