MINIMUM LIQUID FLUIDIZATION VELOCITY IN GAS-LIQUID-SOLID FLUIDIZED-BEDS

Accurate defection of minimum liquid fluidization is essential to the successful operation of gas-liquid-solid fluidized beds, especially wh en particle or liquid properties evolve. A gas-liquid-solid system of 3-mm glass beads exhibits three distinct flow regimes as the liquid ve locity is increased: compacted agitated and fluidized-bed regimes. Mea surements showed that the bed is not fluidized in the agitated bed reg ime. 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 veloc ity. it can be obtained from the standard deviation, the average frequ ency, the Hurst exponent and the V statistic of the cross-sectional av erage conductivity, which can be measured under many industrial condit ions.