An experimental flow regime map to dynamically structure gas–solid bubbling fluidized beds

Employing oscillatory gas flows to create ordered bubble dynamics in fluidized beds represents a promising approach in reactor design, enhancing efficiency, scalability, and control. This study reports an extensive experimental campaign that identifies the operational regime for structuring Geldart B fluidized beds, introducing a novel pattern recognition algorithm to quantify flow stability and distinguish between “structured” and “unstructured” oscillating beds. The analysis reveals the characteristic features of structured units, including enhanced scalability, homogeneity with narrower bubble size and separation distributions, controlled bubble dynamics, and compartmentalized solid mixing. A nondimensional bubble size, derived from natural frequency and two-phase theory, is proposed to describe the relationship between oscillation characteristics and bubble nucleation. This allows the formulation of a general map to fine-tune oscillating bed operations. The study provides the first comprehensive framework for real-time control of structured beds and sets the stage for further exploration in process intensification and scaling.