The gossip on columns

Using the column as a reactor, as BP and its partners are doing, is one way of making the column work harder for its money. Other ways include making the column separate a mixture faster. This involves making the bubbles that form inside the column smaller. 'But to obtain a dispersion with bubbles of, for example, 100 micron diameter, forces stronger than the force of gravity would be needed. Possibilities include rotating distillation columns which use centrifugal forces, or possibly columns in which powerful electric fields operate,' he predicted.

For example, researchers at the University of Sydney are developing 'spinning cone' distillation columns, which are particularly suitable in the food industry for separating sensitive flavour compounds. The column contains a series of trays which have a cone-shape, with the point facing downwards. Some of these cones are fixed to the sides of the column, but these alternate with cones fixed to a central axle which rotates at high speed. The liquid phase flows down the stationary cones under gravity, and up the spinning ones by centrifugal force.