Abstract
In order to produce product in large quantities at narrow space, the tall vessels stirred with multiple impellers are commonly used, in which, solid-liquid agitation, such as crystallization and slurry polymerization, is operated successfully. However, it is not easy to float and disperse the solid particles throughout the vessel. In order to satisfy this condition, the large impeller is desirable but it is expensive, thus the multiple traditional impellers have widely been used in process industries. However, this system makes considerably wide distribution of particle concentration in a vessel compared with the large impeller. Then, in this study, we studied the suspension of solid particles in the vessel equipped with dual traditional impellers, that is, Rushton turbine, pitched paddle pumping up and down. The combinations of the traditional impellers and the optimal installed position and optimal bottom shape were investigated to satisfy the condition of floating and dispersion that is possible to accelerate mass transfer in throughout the vessel. It has been developed by optical method of particle floating and dispersion and by measurement of the distribution of particle concentration that optimal combination of traditional impellers is pitched paddle pumping down and pitched paddle pumping up, and the optimal clearance of dual impellers is same length of vessel diameter, and the optimal bottom shape of vessel is the profiled shape.
