A generalized bubbling turbulent fluidized-bed reactor model

A new reactor model is proposed as a means of representing fluidized-bed re actors which are subject to high enough gas velocities that they operate, o r may operate, in the turbulent how regime of fluidization. The model views the turbulent regime as filling the interval between fully two-phase behav ior, represented by a generalized version of the two-phase bubbling bed mod el of Grace (1984), and a homogeneous (single-phase) structure, subject to axially dispersed plug flow. The two limiting models are merged into each o ther by allowing key parameters to vary continuously with the superficial v t:velocity, U, using probabilistic averaging. The resulting model is shown to give good predictions in comparison with experimental data from the lite rature. In addition, it predicts a smooth transition from dense to dilute-p hase fluidization, consistent with experimental trends. (C) 1999 Elsevier S cience Ltd. All rights reserved.