Liquid-Liquid extraction is a method of purifying a substance. This is achieved by dissolving the crude material in a solvent- in which other parts of the feed material are soluble. This method worked remarkably well in a project spearheaded by Koch Modular, in which the goal was to purify motor oil through the liquid-liquid extraction process.
Impurities are removed from motor oils using a continuous countercurrent extraction process. The extraction step is followed by vacuum distillation to recover the extraction solvent. The entire process was pilot tested at Koch Modular Process Systems pilot plant in Houston, Texas. A SCHEIBELTM extractor was selected for this application.