COUNTERFLOW: PROCESSES, PATENTED FOR LEWATIT®
With the ion exchange resin technology, products and processes are directly and inseparably linked. For this reason, it is entirely logical that the pioneer of fundamentally new ion exchange products should also have assumed a pioneering role in the development of new processes. The countercurrent process was born. Invented and patented by the Lewatit® scientists and chemists, the principles of countercurrent operation represent a significant improvement over the co-current process. It has since been repeatedly perfected, optimized and diversified! Today's Lewatit® countercurrent processes are the farthest developed, the longest tested and the most thoroughly proven. Several thousand units have so far been built using this technology, and the figure is rising constantly.
LEWATIT® TURNS EVERYTHING UPSIDE DOWN
Because no further significant optimization was possible with the co-current technology, the Lewatit® experts began searching for new approaches, and they came up with this completely new design. What they did, quite literally, was to turn things upside down, and this proved to be the key step towards a new solution: With the Lewatit® Counterflow-technology, the regenerant flows through the resin bed in the opposite direction to the feed solution. The special feature of the Lewatit® countercurrent technology is the upflow exhaustion and the downflow regeneration. Upflow exhaustion avoids any compaction of the resin bed and ensures optimal distribution of the treated product flow. With downflow regeneration, the resin lies on the bottom nozzle plate. This prevents reclassification of the resin bed and thus eliminates the possibility of destroying the polishing layer, which exerts a major influence on the quality. The regenerant level is reduced (potential savings of well over 50 %!), and the quality of the treated solutions is significantly improved.
The most popular counterflow processes mostly invented by LANXESS are: