Industrially Relevant Radioactive Particle Tracking Study On The Motion Of Adsorbent Granules Suspended In A Pilot-Scale Water-Air Three-Phase Fluidized Bed

The information obtained by one-dimensional Radioactive Particle Tracking is used to make an industrially relevant description of the macroscopic mixing of a three-phase bubble column. The objective is to characterize and compare the solid motion of granular activated carbon (d(p) = 1 mm) and calcium alginate beads (d(p) = 5 mm), widely used as adsorbents for pollutants and as support for catalysts, enzymes, and living organisms. The particles are suspended in water with upflowing air into a 0.1 m diameter and a 1 m height bubble column. The liquid-solid suspensions are in batch, and the air superficial velocity ranges within 0.01-0.12 m/s. The solid axial hold-up distribution of the carbon-water-air system is biased towards the bottom of the column, while the alginate-water-air system is more even. The axial dispersion coefficients obtained in both systems have a positive linear behavior within the operating range, which is uncannily marked in the carbon-water-air system, and it is an order of magnitude less than the alginate-water-air system. The contrasts of the two systems are mostly explained as a function of the solid densities. Axial mixing time distribution shows a sharp minimum at the second quartile of the column. Flow regime transition is assessed using information theory. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.