Modeling and flowsheet simulation of continuous fluidized bed dryers

Abstract

Abstract In the current paper a simulation tool based on previous work of Burgschweiger and Tsotsas [1] is implemented within the framework of the flowsheet simulation program SolidSim [4]. The implementation within the flowsheet simulation program allows the simulation of the drying process for many different liquids and solids. It can also simulate the drying of mixtures of different solids. The module computes the vapor loading and temperature of the out flowing gas and the moisture and temperature distribution of the solids at the outlet taking into account their residence time distribution, their particle size and their moisture distribution at the inlet. Furthermore the model has been extended by a simple approach to simulate the drying in an elongated fluidized bed dryer. After validation the model has been used to study the influence of residence time, particle size and inlet moisture distribution in addition to drying of mixture of different types of solid. For the modeling it is assumed, that there is no classification occurring within the bed. This assumption is commonly fulfilled as long as the particle size distribution is not too wide and the fluidization velocity is sufficiently high. In this case the mixing action of the bubbles is dominating the segregation tendencies.