Annular centrifugal extractor

The holdups of the two phases are very small, which is advantageous in certain applications. As the phases are in the co-current flow, they can attain equilibrium. Therefore, the extractor is at best one equilibrium stage. However, multiple units can be configured to form a multi-stage countercurrent extraction unit. There is a need to evaluate the relative merits of the multiple units configuration vis vis the Podbielniak extractor, which offers 4 to 6 stages in a single unit. 

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Xiangming, H., Y. Yushun, Z. Quanrong, and L. Binren. 1998. Recent Advances of Annular Centrifugal Extractor for Hot Test of Nuclear Waste Partitioning Process. J. Nucl. Sci. Technol. 9(3), 157-162. 

Figure 5.7 Annular centrifugal extractor. Source Courtesy of CINC Deutschland GmbH Co. KG.

Alternative The washing can be done in a Podbielniak centrifugal extractor, which is continuous countercurrent extraction. Alternately, the same can be done in a cascade of annular centrifugal extractors configured in the countercurrent mode. It is known that the amount of cold water required and the loss of the API would be far less compared with values for the crosscurrent process [18]. 

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