Implementing a KARR® extraction column in the unit operations lab

• Published in: Education for chemical engineers 2020-07, Vol.32, p.95-101
• Main Authors: Jackson, Scott C., Skaf, Dorothy W.
• Format: Article
• Language: English
• Subjects: Commercial scale up; Experimental analysis; Extraction factor; Karr® column; Liquid-liquid extraction; Undergraduate chemical engineering laboratory; Unit operations laboratory
• ISSN: 1749-7728; 1749-7728
• DOI: 10.1016/j.ece.2020.05.006

•A continuous liquid-liquid extraction experiment using a Karr® column was implemented in the unit operations laboratory.•The effectiveness of teaching key concepts was measured using student surveys and detailed grading rubrics.•The impacts of changing hydraulics on the interfacial area, mass transfer and height equivalent to a theoretical stage were conveyed to the students.•Lab data were used with equipment scale-up guidelines to size a commercial scale Karrr® extraction column. The use of a continuous countercurrent Karr® extraction column for the senior unit operations lab at Villanova University is described. A number of issues were addressed in developing this experiment. These issues included the purpose of the experiment, the specific material system to use, i.e., the composition of the feed, extract and the solute, the volume of materials to process, safety concerns including toxicity and flammability of the materials, waste handling, the analytical technique needed to determine solute recovery, and identification of a design application related to the laboratory data. The experiment described here has been successfully used for three years without any significant problems. Student survey results and report grading rubrics indicate that the students understood important aspects of the fluid dynamics that govern mass transfer in a continuous extraction column and how to use lab data for a commercial design. Students also identified areas for potential improvement.