Multiphase Bioreactor Design

Figure 9.1 Schematic diagram of solid

gas catalysis in a packed bed reactor.

the saturation pressure of the pure compound, obtained from the saturation curves at the
temperature of the gas stream (Tin) as described in Figure 9.2 and using the following
equation:

Then, the key parameter for the development of solid gas bioreactor is the
thermodynamic activity of each species present in the gas phase. This thermodynamic
parameter corresponds to a measure of the “availability” of each compound and strongly
depends on two physical parameters; temperature and absolute pressure.

Atmospheric and reduced pressure reactors

Two main strategies are used for creating a gas for solid/gas biocatalysis system, based
either on saturation by an organic molecule of a carrier gas or by vaporisation of liquid
molecules using a liquid gas flash operation in a carrier flow. Most reactors described in
the literature use the first approach, and simple calculations and controls allow a precise
control of all the operating parameters of solid/gas systems.
If one considers the following bioreactor depicted in Figure 9.3 in which different
saturated gases are mixed to produce the final gas, the control of operational parameters
can be realised as indicated below.
One can assume that a carrier gas, after bubbling in a substrate solution at a controlled
temperature, is in equilibrium with the liquid phase and so the partial pressure of the
substrate in the gas leaving the saturation apparatus is equal to the vapor pressure

Multiphase bioreactor design 266