Experimental investigation on the hydrodynamics of a gas–liquid–solid fluidized bed using vibration signature and pressure fluctuation analyses

Simultaneous analyses of vibration signatures and pressure fluctuations were performed to investigate the hydrodynamics of a conventional three-phase gas–liquid–solid fluidized bed over a wide range of operating conditions. Non-intrusive vibration signature and pressure fluctuation signals were acquired by means of accelerometers and a piezoresistive pressure transducer, respectively. Comprehensive study on the standard deviation of pressure fluctuations was conducted simultaneously with two new statistical analyses on the pressure fluctuations, namely signal energy and average cycle frequency, which presented a new method of determining minimum liquid-fluidization velocity. This enabled further investigation on the dual effect of solid particles on the local hydrodynamics in the three-phase beds. The vibration analysis of the bed was introduced as a novel and non-invasive tool, which proved to be a robust representative of the global governing regimes suggesting a new approach on the dual effect of solid particles on the bed global hydrodynamics. These methods can pave the way towards the non-invasive hydrodynamic characterization of industrial three-phase reactors.