No abstract

No abstract

No abstract

No abstract

No abstract

No abstract

Experimental work is reported on the drawdown of floating solids by agitation inside a tank. The effects of baffle configuration, type of impeller, solids concentration, and impeller clearance from the tank bottom, on the minimum drawdown speed and associated power input, are discussed. The baffle configuration did not significantly influence the minimum drawdown speed but strongly determined the power required. The power number increased with the number of baffles in any configuration. The drawdown speed was highly dependent on the type of impeller: highest and lowest values were recorded for the propeller and paddle, respectively. Solids concentration and impeller clearance from the tank bottom had a small effect on the minimum drawdown speed. However, the latter strongly affected the associated power input. Two preferred stirrer/baffle arrangements determined were (1) one baffle (three-bladed propeller) and (2) four baffles (six-bladed turbine) a t an impeller clearance of two-thirds of the liquid depth from the tank base.In several chemical processing operations, mechanical agitators are used to suspend solids in liquids to enhance solid-liquid mixing for catalytic and mass-transfer purposes. Suspension of solids heavier than the liquid medium has received extensive attention, and several correlations for calculating the required speed of agitation for complete suspension have been developed and published (Aeschbach and Bourne, 1972;Baldi et al.

No abstract