(655c) Scaling Up Liquid-Liquid Extraction Columns From Pilot Plant Tests

Scaling Up Liquid-Liquid Extraction Columns from Pilot Plant Tests

Distillation columns can often be designed without pilot plant testing with a high assurance that the required performance can be achieved in the production columns.  However, experience has proven that the most prudent way to design a liquid-liquid (LLE) extraction column is by first testing in a pilot plant column and then using proven scale-up techniques to size the production column correctly.  As the diameter of an LLE column increases, the tendency for back mixing to occur also increases and this results in lower efficiency.  Thus, the key for scale-up is to understand how the efficiency changes with diameter and to factor this into the design of the production column.  This paper will cover the scale up techniques for two agitated extraction columns; the SCHEIBEL^® Column with rotating impellors and the KARR^® Column with a reciprocating plate stack.  Over years of experience with many different LLE systems, proven scale up correlations for these two columns have been developed and used for the design of production columns with performance guarantees.  A case study for each column will be presented including the data generated in the pilot plant and then the calculation for sizing the production columns.