Raschig USA Inc.

A new packing structure with innovative advantages


Courtesy of Courtesy of Raschig USA Inc.


The Raschig Super-Pak is a new geometric packing design which through an innovative structure, has three major advantages over other high-performance packing: lower pressure drop, higher capacities, and better separation efficiency. The performance data measured at the Separations Research Program (SRP) at the University of Texas at Austin are presented and evaluated in comparison to other high-performance and standard structured packing.


Today, the use of structured packings for separation tasks in distillation, absorption, desorption, and extraction columns is the standard solution when it comes to realizing excellent separation performance with very low pressure drops. 

Today’s standard packings consist of a wave-shape profiled sheet, wherein the waves mostly run with an positioning angle of 45° or 60° to the horizontal, see Fig. 1. Studies relating to fluid dynamics in standard packings have shown that at the crossing points of the packing layers, an increased pressure drop comes about due to the abrupt redirection of the flow of gas. This in turn leads to localised retention of the liquid, followed by early flooding of the structure.

In the mid-90’s, the high-performance packings that we know today came onto the market. This is characterised by a change in geometric design at the ends of the packing layers, see Fig. 1. Depending on the provider, three different designs are currently available. The thing that all designs have in common is the vertical position of the wave-like profiles in the zones at the ends of the packing. While Montz allows the transition to the 45° position to run well into the centre of the packing and only realizes this on the lower side of the packing, Sulzer makes the transition on both the upper and lower sides of the packing layer with a relatively short transition area. Koch-Glitsch is pursuing a similar concept as Sulzer; however, it realizes the transition with an abrupt change in the angle. The result of this change to the geometric design in the transition area of the packing layers resulted in substantial increases in capacity.  

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