3. Choice of internal equipment

At present (1994), the columns most often installed are :

• or columns with perforated trays or valves;

• either columns with modern bulk packing (derived from Pall rings and Berl saddles) or structured packing with low pressure drop and high efficiency.

This does not rule out the use of other, more appropriate types of equipment in particular cases, or simply as a matter of tradition.

The methods to be used for the general design and sizing of tray columns are set out in the articles and . The article deals with the same issues concerning packed columns.

The article is devoted to pilot columns, which are often needed to solve new separation problems;...