Over the years, many forms have been proposed for tower packing elements, but few of them are widely used. Probably the oldest form of packaging of a drop tower in the main commercial use is the rashiga ring. This package is a simple cylinder with a length equal to the outer diameter. It is made of ceramics, metals, plastics and carbon. Two modifications of this form are the Lessing ring and the transverse septum ring. Both of these forms use internal sections. These packages were installed both in a drop and folded way.
Further modification of the main cylindrical shape assembles the installation of a spiral inside the cylinder. The inner part of this ring may contain a single, double or triple helix. This spiral ring package is usually made of ceramic and should only be installed by stacking.
The first modern pack was the Berl saddle, developed in the late 1930s. This shape has a significantly increased surface area per unit of packaged volume compared to a raschig ring. Another improved form was the Intalox saddle, developed in the early 1950s. This design has two different radii of curvature, which provide a greater degree of randomness in the compacted layer.
In the early 1950s, a significant improvement was made in the shape of the Raschig BASF ring. Their development, called the Pall ring, consists of a cylinder of the same length and diameter, with ten fingers punched from the wall of the cylinder, which extend inward the inside of the packaging element. Although the palla ring has
the same geometric surface area as the Raschig ring, the inner surfaces of the Pall ring are much more accessible to gas and liquid flows due to
holes through the wall. Subsequent annular gap configurations, such as Hy-Pak packaging, which further increase the percentage of internal surface area, the filler has the ability to come into contact with gas and liquid.
Another modification of the Pall ring was developed by Mass Transfer Limited. Their cascading mini-ring is also a cylinder with fingers punched from the wall jutting into the ring; however, the cylinder height is only one third of the outer diameter. It is said that this form is oriented mainly when dropping into the packed layer.
The new packaging element combines the advantages of the Intalox saddle shape and the modern packaging of the ring. This packaging with an intalox metal tower or IMTP packaging (Norton Chemical Process Products) was developed by Norton in the late 1970s and made only from metals.
The shape of the thread packaging was developed by Dr. A. I. Teller in the 1950s. This cassette is made of plastic only. To meet the demand for packaging with very low pressure drop for use in pollution control applications, Intalox Snowflake packaging has been developed. This plastic packaging has been released since 1987. This unique shape provides the maximum number of intermediate droplet points with a uniform shape. This feature causes a constant renewal of the surface of the liquid, which greatly increases the efficiency of mass transfer. This package has been used in wetting, draining, scavengers, scrubbers and strippers, etc.
Since it is still in development, this is the story of the history of the random packing history, it includes the main type of drop wells.
