Modeling of the Concurrent Gas-Liquid Trickling Flow Through a Packed-Bed Reactor to Predict Interfacial Area

Abstract

A wavy annular flow model in a packed-bed is developed by introducing the shape of waves in a thin liquid film to predict the local interfacial area. The trickling flow regime in a packed-bed is often approximated by an annular flow through a narrow circular channel in which the continuous gas and liquid are completely separated by a smooth and stable interface. Most of the existing models for the trickling flow utilize balance equations for each phase to predict hydrodynamics parameters: liquid hold-up, interstitial velocities, pressure drop, or void fraction. However, the smooth and stable annular flow may not result in an accurate prediction of the interfacial area between gas-liquid phases in a packed-bed. Therefore, a wavy annular flow model is introduced to predict the more accurate interfacial area. This is important because the transport of mass, momentum, and energy is proportional to the interfacial area between gas and liquid phase. Because of the annular flow model, the ratio of film thickness to the equivalent channel diameter can be expressed as a function of only void fraction. The two-parallel wire probe allowed to measure the local film thickness has been used to obtain the shape of the interface. By integrating the local interfacial areas over a certain time period, the local interfacial area is evaluated. The interfacial areas predicted by the presented model are comparable with the empirical correlations developed in the past decades.