Alfa-Laval extractor

The Alfa-Laval extractor (213) can give up to 20 theoretical stages in one unit. Depending on the system being handled, the capacity of the standard unit ranges between 5.7 and 21.2 m /h (1500—5600 gal/h). Antibiotic extractions and petrochemical processing are typical appHcations. 

The Alfa-Laval extractor contains a number of perforated cylinders revolving around a vertical shaft. The liquids follow a spiral pa about 25 m long in countercurrent fashion radially and mix when passing through the perforations. Up to 20 theoretical stages can be achieved. 

Centrifugal Force Flow through baffles Westfalia Extractor Robatel Extractor Podbielniak Extractor Alfa Laval Extractor... 

Figure 13.41. Working principle of Alfa-Laval centrifugal extractor...

The Podbielniak and Alfa Laval centrifugal extractors are essentially continuous differential contactors. The Westfalia and Robatel centrifugal extractors contain discrete mechanical stages, and flow from one to another is effected by spill over discs and skimmers according to usual centrifugal clarifier practice. As the number of discrete stages is increased, the allowable flow rates are proportionately decreased. 

---