Identifying optimal flow patterns in gas–solid micro‐fluidized beds and criteria analysis

Micro‐fluidized bed reactors (MFBRs) enable precise reaction analysis by suppressing gas back‐mixing. Using multiscale computational fluid dynamics simulations, we elucidate how particle properties and operating parameters govern MFBR hydrodynamics, establishing quantitative criteria for identifying plug flow. By systematically varying gas velocity, bed diameter, and static bed height for different particle systems, a dimensionless criterion ( Bm ≤ 0.015) is derived from RTD parameter correlations, effectively discriminating nonideal features and ideal plug‐flow's unimodal symmetry. Our results demonstrate that the Bm criterion exhibits strong sensitivity to nonideal flow characteristics, with decreasing Bm values effectively suppressing RTD distortions (tailing and multi‐peak phenomena) while promoting convergence toward ideal plug‐flow's unimodal symmetry. Furthermore, plug flow conditions are generally satisfied for Geldart A and B particles at D t ≤ 15 mm, while stricter diameter control is required for large‐particle systems due to pronounced wall effects. This mechanistic framework enables standardized MFBR design for precise reaction kinetic studies.