Solvent extraction Podbielniak

Solvent extraction Podbielniak extraction Membrane solvent extraction Coupled transport Minimum emulsification and associated entrainment loss Enhanced selectivity and concentration... 

During recent years pilot scale equipment, smaller than the prototype pilot plants described and capable of operating with exceedingly high efficiency, has been designed. Such equipment as the York-Scheibel solvent extraction tower and the Podbielniak countercurrent centrifugal mixer and extractor are typical. Data from this equipment may be correlated with commercial performance. 

One attempt to improve the situation has been successful for small to moderate scale operations where high purity is required—namely, the Podbielniak centrifugal counter-current contactor and separator, which dominates the solvent extraction phase of penicillin manufacture. 

Podbielniak WJ, Kaiser HR, Ziegenhorn GJ. Centrifugal solvent extraction. Chem Eng Prog Symp Ser 1970 66(100) 43-50. 

For recovery, the broth is clarified by means of rotary vacuum filters. The penicillin, being acidic, is extracted from the aqueous phase into a solvent, such as methyl isobutyl ketone or amyl acetate, at a pH of 2.5 by means of a continuous countercurrent extractor, such as a Podbielniak. The penicillin is then reextracted with an aqueous alkaline solution or a buffer at a pH of 6.5-7.0. About 90 percent recovery yield is typical at this step. The... 

Extraction is a process that utilizes the difference in solubility of the product of interest between two immiscible phases. Liquid-liquid extraction is commonly used in classical biotechnological downstream processing for production of antibiotics and other small molecules. The second liquid phase is usually a water immiscible organic solvent. Reciprocating plate, Podbielniak centrifugal extractors, Delaval contactors, and Westfalia extraction-decanters are examples of some of the equipment available for carrying out extraction. 

Common penicillin extraction solvents are amyl- and butyl-acetate or methy-lisobutylketone. As penicillin is extracted as a free acid at pFl 2-2.5 and the molecule is instable at this pFl, extraction occurs in a counter-flow using Podbielniak- and Luwesta-centrifugal extractors to shorten the contact time with the solvent and to prevent product decomposition. 

---