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Hydrodynamics of turbulent bed contactor with non-Newtonian liquids: Net pressure drop and minimum fluidisation velocity (part 2)



The study investigates the hydrodynamic behaviour of non-Newtonian liquids under different operating conditions in a turbulent bed contactor (TBC). Hollow plastic spheres were fluidised in an air stream flowing counter currently to an aqueous solution of carboxy methyl cellulose (CMC) of an apparent viscosity ranging from 5 to 25 mPa s. A set of experiments was carried out to investigate the net pressure drop and minimum fluidisation velocity of the process. The column was operated at different superficial gas velocities, liquid flow rates, CMC solution concentrations and static bed heights. Results show that the net pressure drop is independent of the superficial gas velocity, but it increases steadily with liquid flow rate and static bed height. However, it remains almost invariant with a relatively low CMC concentration (0.2–0.4 wt%), and it augments gradually as the CMC percent exceeds the threshold of 0.4 wt% which corresponds to a more viscous liquid solution. The minimum fluidisation velocity decreases with a CMC concentration lower than 0.5 wt% approximately, but increases as the CMC percent exceeds 0.5 wt%. The study presents a new insight on the behaviour of non-Newtonian solutions in TBC columns.