Material specific drying kinetics in fluidized bed drying under mechanical vibration using the reaction engineering approach

Abstract

The accurate modeling of vibrated fluidized bed dryers plays an important role in the design and optimization of industrial drying processes. Understanding the impact of vibration on the hydrodynamics of the bed, as well as the drying kinetics, is crucial for accurate modeling. The influence of vibration on the drying kinetics was investigated. It could be shown that vibration reduces the minimum fluidization velocity (umf) and thereby enables the operation of fluidized bed dryers at lower gas velocities. The reduction of umf is particularly pronounced at the resonance frequency of the bed material. However, once the powder was fully fluidized, no impact on the drying kinetics was observed.The Reaction Engineering Approach (REA) is one of the methods used to describe the drying kinetics with one material specific curve. In this work, it was shown that REA curves can be determined based on batch drying experiments in fluidized beds. Porous particles of Geldart groups A, B and D with particle sizes and densities similar to food products were investigated and their REA curves were experimentally determined. Comparison of the derived REA data with established material specific drying curves from literature shows high similarity. Hence, the REA data from fluidized bed experiments is suitable for the modeling and simulation of fluidized bed drying processes.