Insights on Advanced Diagnostic Approaches for the Identification of the Total Recirculation Regime in Stirred and Sparged Tank Reactors

The operating hydrodynamic regime influences mass transfer in gas-sparged stirred tank reactors (SSTRs). Among the hydrodynamic regimes, the total recirculation regime (TRR) is preferred for reaction kinetics studies, as it provides optimal gas–liquid (G–L) interactions while minimizing hydrodynamic limitations. In this review, we present a perspective on advanced integrated diagnostic approaches as a way forward for capturing the complex interfacial dynamics of bubble behavior, thereby enabling accurate identification of TRR boundaries and reliable determination of kinetic parameters and their hydrodynamic origins. As an outcome, these approaches support cost-competitive refinery operations, as illustrated by the LPG desulfurization case. Although we focus on the SSTR kinetics of thiol oxidation, using LPG desulfurization as a case, the insights gained apply to similar G–L reaction systems in which the fundamental hydrodynamics of multiphase turbulent interactions must be investigated to optimize reaction kinetics.