Minimum liquid fluidization velocity in gas-liquid-solid fluidized beds

Accurate detection of minimum liquid fluidization is essential to the successful operation of gas‐liquid‐solid fluidized beds, especially when particle or liquid properties evolve. A gas‐liqid‐solid system of 3‐mm glass beads exhibits three distinct flow regimes as the liquid velocity is increased: compacted, agitated and fluidized‐bed regmes. Measurements showed that the bed is not fluidized in the agitated bed regime. Pressure gradient and bed height measurements do not provide the minimum liquid fluidization velocity; instead, they offer the velocity between the compacted and agitated bed regimes. Time‐averaged signals are not reliable for determining the minimum liquid fluidization velocity. It can be obtained from the standard deviation, the average frequency, the Hurst exponent and the V statistic of the cross‐sectional average conductivity, which can be measured under many industrial conditions.