determined largely by the slip velocity between the gas and
liquid phases. The value of kLaGL is also affected by the physical
properties of the gas–liquid system, the velocities of the
gas and the liquid, the lyophobicity of the solid and the solids
holdup.
The axial dispersion coefficient in either the gas or liquid
phase characterizes the amount of mixing with a single parameter,
Dax,G or Dax,L. The axial dispersion within a column
may be quantified by performing tracer experiments. A pulse
of non-transferring tracer is introduced at the phase inlet and
the residence time distribution of this pulse is obtained at the
reactor outlet. The outlet concentrations are modeled with an
axial dispersion model as given in Eqs. (1) and (2) with the
value of kLaGL set to zero; and for co-current upflow of gas and
liquid: