This manuscript provides a comprehensive overview of
gas-inducing
reactors (GIRs) and identifies areas for further investigation. It
examines the gas induction systems available in the literature, categorizing
them into conventional types of 11, 12, and 22, and highlights the
importance of focusing on double-impeller systems as a practical solution
for large-scale GIRs. The work includes a thorough review of applied
models and correlations for estimating critical impeller speed (N
C), induced gas flow rate (Q
G), influence of fluid’s physical properties, power
consumption (P
G), gas holdup (εG), and gas–liquid mass transfer coefficient (k
L
a). Furthermore, it discusses
the necessity for further research in understanding non-Newtonian
flow behaviors, the impact of fluid physical properties across a broad
range of fluids, the interdependence of variables, the identification
of key parameters, and stability analysis in large-scale reactors.
Additionally, the manuscript addresses the challenges and limitations
in experimental techniques, equipment utilization, scale-up processes,
and the application of modeling tools such as artificial neural networks
(ANN) and computational fluid dynamics (CFD) in the context of gas
induction.