Fluid Dynamics of the Freeboard in a Fluidized Bed Reactor

摘要

The present study focuses on the fluid dynamics of the gas-particle freeboardflow, whereas a subsequent study will cover the chemistry. The objective of the present thesis is to increase the insight in the physical processes that govern the freeboard particle flow. Special attention has to be paid to the lateral transport of particles and the often observed phenomenon of a downflowing wall layer of solids, which has not been explained satisfactorily up to now. In order to achieve this, detailed experiments have to be performed which provide data on the local flow structure. In addition, the freeboard flow has to be modeled at least two-dimensionally, incorporating the essential physical processes. The resulting model of the freeboard flow should firstly be capable of predicting the local properties of both the gas flow and the particle flow. This prediction has to serve as a basis for the subsequent modeling of the freeboard chemistry. Secondly, the model should serve as a basis for studying the consequences of the scaling up a fluidized bed installation from lab scale to industrial size.