MAXIMIZATION OF RECOVERY OF SPIRULINA-PLATENSIS IN A STAGED PROCESS-BASED ON INERTIAL MIGRATION

Branched tubes have been employed to concentrate dilute solid-liquid s uspensions. They utilize the nonuniform radial particle distribution r esulting from lateral particle migration under laminar flow conditions to concentrate the suspension by directing the portion of the flow fi eld near the main tube wall through a branch. Branched tube separation devices can be used in a continuous mode, and by employing a staged s ystem, where each stage is made up of a set of branched tubes, it is p ossible to achieve high recovery, good concentration factors, and larg e throughput. Initial studies were directed toward obtaining large con centration factors, i.e., higher separations. This work examines the m aximization of recovery, which is defined as the fraction of inlet par ticles recovered in the concentrated stream. Suspensions of Spirulina platensis, a microalgae, were concentrated using a single-branch syste m, and it was found that by using a 600-mu m diameter main tube, the s uspension could be concentrated 36 times using 7 stages with an overal l recovery of 92.1%.