(128c) Challenges for Scaling up Liquid-Liquid Extraction Columns

Liquid-liquid extraction equipment has always been difficult for scale-up because modeling techniques and computer simulation cannot effectively represent the complexity of the process taking place (e.g. droplet breakup and coalescing, mass transfer rates, interface behavior, axial and radial mixing, etc.).  Thus, the design of extraction columns has relied primarily on pilot plant testing and then known scale-up correlations that are specific to each type of extraction column.  However, scale-up from pilot plant testing can be problematic for certain types of liquid-liquid extraction processes.  This paper will address several-scale up issues that have been encountered in specific extraction processes, using actual process examples that were tested in the pilot plant.  For each application, the solutions for the scale-up from pilot plant results to the ultimate commercial equipment will be discussed.