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 (${\epsilon }_{g,s}$) via electrical resistance tomography (ERT), we identified three distinct flow regimes and two transition velocities using ${\epsilon }_{g,s}$-based criteria. Furthermore, we employed pressure transducer and ERT to analyze how gas velocity (U_g), water velocity (U_w), and particle size (D_p) influence pressure fluctuations, minimum liquid fluidization velocity (U_mf), and gas and solid hold-ups distributions. Results showed that U_w and D_p significantly influenced pressure fluctuations, while U_g affected pressure fluctuations mainly for large particles. U_mf increased with D_p but remained unaffected by U_g. Higher U_w and D_p led to more uniform distributions of radial gas and solid hold-ups, with U_g influencing distribution only in the fixed bed regime. Finally, the using Box-Behnken design (BBD) and analysis of variance (ANOVA), significant interactions between U_g and D_p for the average differential pressure, and between U_w and D_p for ${\epsilon }_{g,s}$ 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.