A scaling law for circulating fluidized beds

Abstract

Based on the Clustering Annular Flow Model (CA model), a scaling law for circulating fluidized beds, i.e. a set of necessary conditions to attain a geometrically similar flow structure in a scale model, is derived. To validate the theory an experiment was performed by using two geometrically similar circulating fluidized-bed cold models (CFB A: 200 mm I.D., 1600 mm high; CFB B: 50 mm I.D., 400 mm high). The longitudinal voidage distribution, the condition of choking-like transition and the radial distributions of the cluster velocity were obtained for the two CFBs where the operating conditions were adjusted to be consistent with the scaling law. Good agreement was found over a wide range of operating conditions between the performances of the two cold models, and the validity of the proposed scaling law was confirmed. © 1989, The Society of Chemical Engineers, Japan. All rights reserved.