The study is focused on modeling of gas maldistribution of aerated liquid systems in a
multiple impeller bioreactor. The phenomenon may or may not depend on column design. The latter
case is dependent merely on bed fluid dynamics and could be treated by using the methodology of the
residence time distribution (RTD) theory. Accordingly, a specific methodology is proposed, as follows:
the fermenter has been modelled as a reactor network involving a combination of zones representing
basic ideal flow patterns. The methodology is based on the wide-spread experimental gas tracer
technique extended by a new systemic identification approach. The approach is based on a Mellinmodification
of the Laplace transform over the relevant equations. The method allows zero-time
solutions for identification analysis. Unlike the diffusion model approximation, the technique
considered allows exact approximation of the RTD curves with circulation. The proposed transfer
function represents adequately the bioreactor gas maldistribution thus allowing fast overview of the
studied reaction and prompt feed back control on the physical situation
