Biodiesel Production from Waste Oily Sludge by Acid-Catalyzed Esterification

Guoqing Guana; Katsuki Kusakabe

Authors

Guoqing Guana North Japan Research Institute for Sustainable Energy, Hirosaki University, 2-1-3 Matsubara, Aomori 030-0813, Japan Author
Katsuki Kusakabe Department of Nanoscience, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan Author

Keywords:

Biodiesel, esterification, free fatty acid, ferric sulfate

Abstract

Waste oily sludge (WOS) with high free fatty acids (FFA) content was used as a feedstock for biodiesel production. Oil content was firstly extracted from WOS containing water using hexane, and approximately 71 wt% of the extracted oil was FFA. The extracted oil was esterified with methanol to produce biodiesel using sulfuric acid or solid ferric sulfate catalyst. The fatty acid methyl ester yield reached above 86% for both catalysts. In addition, ferric sulfate can be easily recovered from the reaction system and reused two times without rapid decrease in the catalyst activity.