Collect. Czech. Chem. Commun. 1993, 58, 1055-1068

The Measurement of Voidage of Nonuniformly Fluidized Bed by Means of the Wall Pressure Signal

Ján Beňa and Ivan Havalda

Department of Chemical and Biochemical Engineering, Slovak Technical University, 812 37 Bratislava, Slovak Republic


By the wall pressure signal, ∆px, from a nonuniformly fluidized bed is here termed the excess pressure at a wall of open column over the atmospheric pressure measured at a distance x from distributor. The relation was investigated between the wall pressure signal, ∆px, and some specifically defined voidages of a so-called standard bubbling bed characterized by the fact that the ratio of the experimentally determined pressure drop for minimum fluidization, ∆p0,mf, and of the theoretical pressure drop, ∆pt, is approximately equal to the unity. We have shown that under certain conditions, the time-volume averaged voidage, ε, of this bed can be determined in terms of simple relation (13).