U-column - Pulsed Sieve Plate Twin Columns

• A vertical, cylindrical tube containing a packing of horizontal, perforated plates
• Two larger horizontal tubes at the top and at the bottom to allow phase disengagement
• A pulsatory device, a pneumatic operated membrane, in between the two columns that periodically moves the liquids inside the columns up and down.

The twin column arrangement has the advantage that the pulses are swinging like a gyratory movement between the two columns, giving low energy input and a smooth operation, no heavy lifting of liquid pillars. Both columns don`t need to have the same function, e.g. one can be designed for extraction, the other for stripping.

General Description of a Pulsed Column
A pulsed sieve-plate extraction column is an often-used industrial equipment because of its considerable flexibility, high throughput and high separation efficiency. Another advantage of the column is there insensitivity to contamination. On the other hand, there are factors, e.g. the drop coalescence, the ability of the used liquids to wet the plate surfaces and the effect of impurities that are poorly understood and that limit the use of theoretical approaches. Therefore, pilot plant tests may be necessary to design a column.