Simulated Moving Bed Strategies and Designs: From Established Systems to the Latest Developments

The simulated moving bed (SMB) technology has evolved significantly since its inception. The appearance of several variants to conventional SMB has led to better performance in productivity and product purity, and lower operating costs, thus creating new opportunities for different applications. This trend is clearly visible in the increasing number of papers and patents published in this field in recent years. This review aims to gather and discuss several modifications and operation modes that have been proposed, from the most well-known Varicol and PowerFeed to the latest Intermittent-SMB and variable external stream systems, giving particular emphasis to innovations and applications of each SMB strategy. SMB valve designs are also covered in this article for their importance in the application of the operation modes discussed, which require ever more flexible units capable of variable switch times, column expandability, zone bypasses, and reduced solvent consumption while still avoiding contamination through line sharing.