Degree Name



Chemical Engineering


Ira A. Fulton College of Engineering and Technology

Defense Date


Publication Date


First Faculty Advisor

Randy Lewis

First Faculty Reader

Matthew Memmott

Honors Coordinator

Dean Wheeler


GEO, vegetable oil, soap, waste vegetable oil


This thesis examines the impact of vegetable oil usage in industrial and home settings on the properties of the vegetable oil and how its usage in soap affects the final product. Waste vegetable oil (WVO) is often used to make soap as a way to be more environmentally-friendly and create soap at a low cost in developing countries. Two settings are examined: home usage (i.e. short-term, small-scale usage) and industrial (i.e. long-term, almost continuous usage). This thesis found that lightly used oil (household use) had little to no impact on the quality of the oil, except for its scent. This resulted in a bar of soap that had very similar properties to soap made from fresh oil, except for it was somewhat brittle. However, when oil was used extensively the properties of the oil changed dramatically, including a deepening of the color, free fatty acid (FFA) content increase to approximately 5%, and an acquired scent. This resulted in a bar of soap that was darker in color, and had less lather than fresh oil soap (by 1.4 on a scale of 5). The industrial WVO had the advantage of reacting quickly with the lye to make soap, allowing the soap making process to take less time, and for the bar of soap to reach a usable stage quicker, most likely because of the high FFA%. These results demonstrate that using lightly or heavily used vegetable oil in soap results in a high-quality product for a very low cost.