In the design of fluidized-bed units

determination of TDH (Transport Disengaging Height) for the dilute-phase zone appears to be of primary importance. Presently

the empirical curve developed by Zenz and Weil in 1958 has been widely used. In the present paper

taking the equation for the motion of single particles as the basic starting point

methods for calculating gas velocity

particle velocity

and particle stagnation time and rising height in gas-solid flow

have been developed through theoretical analysis

resulting in an eight-parameter expression

Equation(15)

for computing TDH. This equation includes more parameters than given in any previous work

and conforms much better with experimental results. It is

henceforth

recommended for design work.