Ktihni column

Countercurrent columns with additional kinetic energy input have found a broad range of industrial applications [42-48]. Examples of extraction towers with energy input are pulsed towers, pulsed packed columns and pulsed perforated-plate towers. A number of units with some form of mechanical agitation are also used (Karr column, Scheibel column, Oldshue-Rushton column, Ktihni column, RZE extractor, RDC and ARD extractor, Graesser contactor). 

Fischer [125] compared the suitability of a -paddle stirrer with vertical (free and also partly covered on both sides) and pitched paddles with a rotating disc for use in an agitated extraction columns (type Ktihni) and found, that the disc was not suitable for dispersion, whereas the three paddle stirrer arrangements were comparable in performance. 

Rotating-Impeller Columns A number of different rotating-impeller column extractors have been proposed and built over the years. Only the Scheibel and Ktihni designs are reviewed here. For information about the Oldshue-Rushton design, see the previous edition of this handbook. Also see Oldshue, Chap. 13.4 in Handbook of... 

Most large-scale equipment for liquid-liquid extraction is available for two-phase extraction and usually multistage systems have to be used for obtaining high yields. Ktihni type columns, Podbielniak centrifugal extractors and disk and bowl centrifuges have been used (Kula et al. 1981 Veide et al. 1983 Cunha and Aires-Barros 2002). 

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