College of Engineering

Jesse Efymow

College of Engineering Chemical Engineering

Faculty Mentor: Dr. Richard A. Cairncross Chemical & Biological Engineering

Purification of Free Fatty Acids from Wastewater Residual Greases

Brown grease is a low-value, dirty form of lipids that are extracted from wastewater systems. Prior research at Drexel has demonstrated conversion of brown grease into crude biodiesel and has identified removal of sulfur-containing contaminants as a critical hurdle to meeting biodiesel fuel specifications. This project explores extraction and purification of Free Fatty Acids (FFA) from brown grease prior to conversion to biodiesel. Saponification and acidulation reaction of brown grease with filtration and hexane extraction enables converting triglycerides to FFA, removing insoluble impurities, removing unsaponifiable impurities, and maximizing the yield of FFA. The FFA produced is lighter in color, solidifies at a higher temperature and has less than half the sulfur content of brown grease. Further purification of FFA to remove color bodies and reduce sulfur content was evaluated using hydrophobic filters, Nano-Filtration, absorption, and Raney Nickel reactions. Purification of FFA provides potential commercial flexibility because it can enter the chemical market or be easily converted into biodiesel or renewable diesel.