Biodiesel Production from Algae Oil

Abstract

In this study, biodiesel production was investigated by the transesterificationreaction from algae oil. For biodiesel production, the oil obtained from Chlorellaprotothecoides type algae grown in freshwater with 5% thermal water was added tofully automated closed-loop system high-tech pyramid photobioreactors and adaptedfor oil production, which had a low acid value (0.23 mg KOH/g). Because of this, basecatalyst transesterification was applied. For the transesterification reaction, 99.7%purity of methyl alcohol as alcohol and 99.9% purity of potassium hydroxide (KOH)was used as a catalyst. In order to determine the most suitable conditions for theproduction of biodiesel from algae oil, a series of laboratory-scale preliminaryexperiments have been carried out. As a result of the optimization studies, the 6:1methyl alcohol/oil molar ratio, the use of KOH up to 0.75% of the oil by mass, thereaction temperature of 60 °C, and the reaction time of 60 minutes were determined asthe most suitable conditions for biodiesel production. Under these conditions, 96.4%methyl ester yield was obtained, and kinematic viscosity and density values of the finalbiodiesel product were measured as 4.493 mm2/s and 882 kg/m3. As a result of thephysical and chemical analysis of the produced biodiesel, it has been determined that ithas an ester content of over 96% and that the free and total glycerol content withmethanol, mono-, di- and tri-glyceride is well below the maximum values specified inthe EN 14214 and ASTM 6751 biodiesel standards. However, properties such asviscosity, density, flash point, cetane number, acid value, sulfur and water content werefound to be compatible with the specified standards. In addition, besides having thestandard fuel properties of the produced biodiesel, its high cetane number (57) andgood cold filter clogging point (-11 oC), makes it an important alternative diesel enginefuel.