Mechanics of batch slurry mixing by means of rotating impellers in a cylindrical vessel

• Main Author: Gamez, Victor Manuel
• Format: Others
• Published: FIU Digital Commons 1998
• Subjects: Mechanical Engineering
• Online Access: http://digitalcommons.fiu.edu/etd/3446

Two slurries with solids concentration of 5 % (wt) and 20 % (w.), with approximate chemical and physical properties of melter feeds found in the Defense Waste Processing Facility of the Savannah River Site were prepared, characterized and mixed in a cylindrical vessel with impellers of different diameters pumping the flow in two different axial directions. The electrical power consumed by each impeller was measured and compared for both slurries. A sampling mechanism consisting of tubes positioned parallel to the vertical axis of the tank was also implemented to ascertain the level of homogeneity developed in the mix. The effects of the diameter of the sampling tubes and the sampling speed were evaluated for different impeller rotational speeds acting on the two slurries. Different startup techniques from a fully-settled condition were also assessed. Results indicate significantly lower power consumption when the impeller pumps the fluid downwards, more representative samples when the sampling tube diameter and sampling velocity are increased, and the lowest consumption of power at the startup from fully-settled conditions by the injection of air in the bed of solids.