NEW DESIGN EQUATIONS FOR LIQUID/SOLID FLUIDIZED BED HEAT EXCHANGERS

Liquid/solid fluidised bed heat exchangers have originally been developed for desalination plants. However, due to their substantial benefits with respect to significantly improved heat transfer and fouling reduction, successful applications also exist in areas such as petrochemical, minerals and food processing as well as in the paper and power industries. The excellent performance of fluidised bed heat exchangers is related to the interaction between particles and heat transfer surface and to mixing effects in die viscous sublayer. In this paper, the results of experimental investigations on heat transfer for a wide range of Newtonian and non-Newtonian fluids are presented. New design equations have been developed for the prediction of bed voidage and heat transfer coefficients. The predictions of these correlations and of numerous correlations recommended by other authors are compared with a large database compiled from the literature.