be ascribed, similarly to the two-phase systems, solely to the decrease of the interfacial
area caused by the enhanced bubble coalescence in the system. In general kL may,
however, vary with the level of micro-scale turbulence (i.e. with the bubbling mode) and
with the particle size, wettability,
Figure 1.4 kLaL. as a function of
superficial gas velocity
full line: data from an ejector
distributor reactor (Zahradník et al.,
1982a); Dr=0.29 m, H=2 m, cs=0
sphericity and adsorbing capacity for the gas component (Alper et al., 1980; Miyachi et
al., 1981; Brück and Hammer, 1986; Pandit and Joshi, 1986). Values kLaL corresponding
to given gas holdup increased substantially with the increasing number of column stages,
i.e. with the number of internal plates. Obviously, such a variation of the functional
dependence kLaL=f(G) can be explained by the relatively weak dependence of bubble rise
Multiphase bioreactor design 14