Two-step methyl ester production and characterization from the broiler rendering fat: The optimization of the first step

In this study, broiler rendering fat obtained from a slaughterhouse was used to produce methyl ester. The acid value of the broiler rendering fat was 5.2 mg KOH g−1. Therefore, it was needed to perform two-step treatment to broiler rendering fat. For this purpose, sulfuric acid was used as a catalyst and methanol was used as alcohol for the first treatment reactions. The variables affecting the free fatty acid level including the ratio of alcohol, catalyst amount, and reaction time were investigated to determine the best strategy for the first step process. After reducing the free fatty acid level of the broiler rendering fat to less than 1%, the transesterification reaction was completed with the alkaline catalyst. Potassium hydroxide was used as catalyst and methanol was used as alcohol for transesterification reaction. The measured fuel properties of the broiler rendering fat methyl ester (BRFME) were compared to EN 14214:2012 + A1:2014 and ASTM D6751-15 biodiesel standards. The BRFME meet ASTM D6751-15 biodiesel standard. Also, the BRFME meets EN 14214:2012 + A1:2014 biodiesel standard except for oxidation stability. According to the results, the oxidation stability property of the BRFME should be improved and should be investigated in detail.