Prafulla Patil, New Mexico State University, P.O. Box 30001, MSC 3805, Las Cruces, NM 88003-8001 and Shuguang Deng, Chemical Engineering Department, New Mexico State University, New Mexico State University, P.O. Box 30001, MSC 3805, Las Cruces, NM 88003.
In this comparative study, biodiesel production from waste cooking using ferric sulfate and sulfuric acid catalyst was carried out. The two-step transesterification process was used to get rid of high free fatty acid (FFA) content in waste cooking oil. This process gives yield of about 85-95% using sulfuric acid catalyst and 80-98% using a ferric sulfate catalyst. Ferric sulfate acted as a heterogeneous acid catalyst and showed good activity to catalyze the methanolysis of FFA in the waste cooking oil. This catalyst is environmental friendly, easy to separate and more efficient than sulfuric acid catalyst. The most important variables affecting the methyl ester yield during the transesterification reaction are the molar ratio of alcohol to oil, the catalyst amount and the reaction temperature. The analysis of different oil properties, fuel properties and process parameter optimization of waste cooking oil were studied in detail. The fuel properties of biodiesel produced were compared with ASTM standards for biodiesel and regular petroleum diesel.