Random packing is used in separation columns, such as a distillation column, to increase surface area for vapor/liquid contact so that chemical separation is more efficient. Random packing is designed to maximize the surface-to-volume ratio and minimize pressure drop.
According to different structural characteristics, random packing can be divided into:
Raschig rings, Pall rings , Saddle rings, lessing rings, tri-packs and so on.
The performance of Raschig ring:
(1) Raschig ring is the first artificial packing used, it is easy to manufacture and has been extremely widely used previously.
(2)The practices shown that the Raschig ring is easy to form line contact (please see below picture) due to the large height-to-diameter ratio, and the distribution of liquid is not uniform. Therefore, there is wall flow and channel flow phenomenon for rasching packing.
(3) At present, the industrial application of Raschig ring packing is declining.