Current and Potential Developments in Methods for the Scale-Up and Design of Column Extractors

Abstract

The current state-of-the-art is design and scale-up procedures for column-type liquid-liquid extractors is reviewed. This covers both the hydrodynamical factors which determine column cross-section and throughput, and those which influence mass transfer via drop-size and holdup, mass transfer coefficient, axial dispersion, drop interactions (i.e., breakage and coalescence), and Marangoni effects. The application of these principles to column design and scale-up is then discussed. It is concluded that for the present, both a matrix inversion method, and a simplified analytical method of adequate accuracy both for performance evaluation from pilot scale data, and for the design of both single-solvent and dual-solvent extractors, are the most suitable. Finally, the possibility is considered of developing more advanced methods based both on Monte Carlo procedures and on direct dynamic simulation by computer.

Application Notes for Program ‘COLDSN’ and DUALSOLV appear in Appendix I and Appendix II, respectively.

Keywords:

• Liquid extraction
• extractors
• columns
• design
• scale-up