Multiphase Bioreactor Design

correlations proposed for kSL in the literature (see, e.g., the generally recommended
equation by Sänger and Deckwer, 1981).
Many industrial processes in g-l-s systems are carried out in high pressure, high
temperature reactors (hydrogénation of industrial fats and fatty oils, hydroprocessing
operations in petrochemistry, Fischer-Tropsch synthesis, etc.). Data on hydrodynamics,
mixing and transport characteristics under these conditions, with real systems, should
therefore be obtained.
Scale-up studies should be aimed at examining whether, and to what extent, the
favourable features of multistage units observed in lab-scale experiments can be
preserved in full-size industrial units and ultimately at providing the guidance for
multistage reactors scale-up.

NOMENCLATURE

aL gas-liquid interfacial area per unit liquid volume, m^2 m−^3

c concentration, wt.%

Dr reactor diameter, m

dn plate orifice diameter, m

Ed overall rate of energy dissipation, W

Ei+1,i coefficient of liquid backflow

ed rate of energy dissipation per unit of bed mass, W kg−^1

g gravity acceleration, m s−^2

Hoi slurry height in a column stage, m

kL liquid-side mass transfer coefficient, m s−^1

N number of column stages

Pb bubble bed pressure drop, Pa

∆PW wetted plates pressure drop, Pa

Q volumetric flow rate, m^3 s−^1

uo superficial velocity, m s−^1

ubs bubble swarm velocity, m s−^1

Wen Weber number related to a plate orifice, Wen=unG^2 ρG dn/σ

Y y-coordinate of dimensionless RTD curves

ε fractional holdup

θ dimensionless time

μ dynamic viscosity, mPa s

ρ density, kg m−^3

σ surface tension, N m−^1

Φ energy effectiveness criterion, kg J−^1

Multiphase bioreactor design 22