Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Process Engineering, Biotechnology, Nutrition Technology
The operating characteristics of a Podbielniak model 5,000 centrifugal extractor, having a combined-stream capacity of 450 cc./min. at 5,000 rev./min. and a rotor holdup of 529 cc., were investigated. Variables studied were density difference, rotor speed, light-liquid-out pressure, flow rates, holdup, and number of stages.A technique for holdup determination that comprises displacing either phase in the extractor with the other phase is described and experimentally demonstrated. An equation useful in predicting flooding limits is verified. It is suggested that the effective values of the rotor dimensions in this equation be determined by the behavior of the extractor.A relationship among number of stages, light-liquid-out pressure, and flow-rate ratio is demonstrated by extracting boric acid from isoamyl alcohol with water. With only a few runs this relationship should permit one to map in a family of curves for a particular system and thus rapidly to estimate optimum operating conditions.A procedure is outlined for applying the methods to other systems using similar extractors. First the constants in an equation are estimated from holdup measurements in order to predict flooding limits. Then a few extraction runs are made to estimate optimum operating conditions.
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