Solids distribution in tall tanks

Uniformly distributing slurry solids in “tall” (≥2:1 aspect ratio) process vessels is a significant challenge in the chemical industry. This work determined the performance of various multi-tier agitation systems in uniformly distributing a settling solid throughout water in a “tall” laboratory vessel. It used a 0.445 m ID Plexiglas® tank, with a slurry height of 0.889 m, to determine how solids distribution changes with solids loading (wt.%), impeller speed, and impeller type. Some impeller types uniformly distributed the solids even before energy input exceeded 1.00 W/kg. Significantly higher energy improved solids distribution little because flow within the vessel eventually became choked.