HYDRAULIC TRANSPORT OF A PACKED-BED DURING THE START-UP OF A 3-PHASE FLUIDIZED-BED WITH LARGE GAS HOLDUPS

Experiments were conducted to study the phenomenon of the hydraulic transport of a packed bed due to a sudden start-up of liquid flow in a gas-liquid-solid system. This phenomenon, which deviated from the conventional slugging flow dictated by the column size, may lead to a total or partial entrainment of the particles during the start-up of a fluidized bed reactor system. The effects of the solid particle size and shape of solid inventory, and the operating conditions such as the magnitude of the step change in the gas and liquid superficial velocities, were investigated. The three-phase fluidized bed was operated in the dispersed bubble flow regime using 0.5 wt % tert-pentyl alcohol aqueous solution as the liquid phase. A mathematical model was also developed to account for the transient behavior of such a phenomenon.