Hydrodynamics of fluidized bed flotation column: Experimental and statistical analysis

The hydrodynamic characteristics in fluidized bed flotation column (FBFC) are critical for optimizing fluidized flotation processes, yet understanding the interactions between operating parameters remains a complex challenge. This study proposes a novel method to classify flow regimes and identify transition velocities in fluidized bed flotation columns. By analyzing gas-solid holdup variations (εg,s) via electrical resistance tomography (ERT), we identified three distinct flow regimes and two transition velocities using εg,s-based criteria. Furthermore, we employed pressure transducer and ERT to analyze how gas velocity (U), water velocity (U), and particle size (D) influence pressure fluctuations, minimum liquid fluidization velocity (U), and gas and solid hold-ups distributions. Results showed that U and D significantly influenced pressure fluctuations, while U affected pressure fluctuations mainly for large particles. U increased with D but remained unaffected by U. Higher U and D led to more uniform distributions of radial gas and solid hold-ups, with Ug influencing distribution only in the fixed bed regime. Finally, the using Box-Behnken design (BBD) and analysis of variance (ANOVA), significant interactions between U and D for the average differential pressure, and between U and D for εg,s were identified, with no significant interactions for normalized standard deviation of differential pressure fluctuation. Predictive models with high correlation coefficients were established for these interactions, offering guidance for FBFC optimization.