Multiphase Bioreactor Design

and the linear permeate velocity through the membrane pores, cross-flow velocity, is
expressed by:

(65)

Reynolds number, Re, is also used to define the flux regimen:

(66)

Analysis of reactor series

The previous modeling clearly proves that the MBR acts globally as a CSTR.
Nevertheless, the simultaneous analysis of permeate and recirculate samples (Figure 7.8)
allows verification

Figure 7.8 Conversion degrees

obtained for the 0.1 ml/min flow rate

in permeate and recirculate solutions.

(From Carvalho et al., 2001b)

that the recirculate and permeate concentrations were different whatever the experimental
conditions. The product concentration was always higher in permeate than in recirculate
and the increase depended on the substrate ratio and on the flow rate selected.
In parallel with the global reactor analysis, it can be proposed that the membrane pores
may act like a second CSTR, although with a higher residence time (there is no
recirculation inside the membrane matrix). The main consequence will be the
achievement of higher conversion degrees, when compared with one unique CSTR. Since
the increment in permeate conversion was remarkable this may raise the possibility of
having the inside of the membrane acting as a PFR.

Multiphase bioreactor design 224