MOVING-BED SOLIDS FLOW BETWEEN 2 FLUIDIZED-BEDS

A simplified form of the macroscopic momentum balance for two-phase flow is applied to moving-bed solids flow in an inclined pipe connecting two fluidized beds. The resulting equation shows that the gravity force of the material in the pipe is counter-balanced by the pressure drop across the pipe and the wall friction. In order to account for the wall friction, a friction factor analogous to the Fanning friction factor in fluid flow is defined, and a friction factor correlation is established based on the data of Trees [11]. The friction factor is found to be a function of the solids flow rate and the pipe diameter. The flow curves of moving-bed solids were also constructed based on the data of Trees. The resulting straight lines show the power-law type flow behavior of the solids. And from the power law indices, it has been shown that the data fit well with the generalized friction factor correlation by Metzner and Reed [16]. It is also observed that data of different pipe diameters yield separate flow curves, which is unusual for time-independent fluids. However, the possibility that moving-bed solids may be time dependent can be ruled out because data of different pipe lengths do fall on a single line. © 1979.