Critical rotational speed for a floating particle suspension in an aeratedvessel

The critical suspension speeds of floating particles in a gas-liquid-floati ng particle three-phase system were measured in a multiple-impeller agitate d vessel. Three types of impellers, i.e., simple axial-flow impeller upflow (SPU) and downflow (SPD), disk turbine (DT) and wing turbine (WT), twelve types of baffles and three kinds of gas spargers were used. The influences of impeller types, baffle configurations, gas spargers, gas superfacial vel ocity and particle loading on the critical suspension speeds of floating pa rticles were systematically investigated. The optimum regressions of critic al suspension speeds were respectively obtained for some better combination s of impellers, bafffles and spargers, such as (a) the 45SPU+45SPD+DT tripl e impellers, two high-level baffles and two low-level baffles (symmetric al location), gas spargers, (b) the 45SPU+45SPD+DT three-impeller, standard ba ffle and small gas sparger. Their errors were smaller than 11 %.