Effect of degumming and catalyst type on physiochemical and biodiesel properties of tropical-almond (<i>Terminalia catappa</i>) seed oil

Abstract

This study investigates the effect of degumming process and catalyst type on physiochemical and biodiesel properties of tropical-almond (Terminalia catappa) seed oil (TCSO) extracted via mechanical pressing and solvent extraction method. The oil was degummed using 4% citric acid in amount of 10% by volume of the oil to reduce the acid value, ash content, and water and sediment value of the degummed oil compared to the raw oil. Data obtained show that degumming process reduces the acid value, ash content and water and sediment value from 7.57 mg KOH/g, 0.86 %w/w and 2.48% to 3.82 mg KOH/g, 0.65 %w/w and 2.40% respectively, and the percentage oil yield was 56.30±1.50%. Biodiesel was produced using a two-step reaction system from raw and degummed TCSO catalyzed by NaOH, KOH and CaO/Al₂O₃. The process yielded a higher yield (97.20±0.35) of biodiesel from degummed oil catalyzed by CaO/Al₂O₃. The fuel properties of the biodiesels were found to fulfill both ASTM D6751 and EN14214 biodiesel standard except the raw biodiesel. this study confirm that degumming process improves the susceptibility of oil for biodiesel production and that heterogeneous base catalyst produce higher yield and quality fuel than their homogenous counterpart.

Keywords: Degummed, Transeterification, Biodiesel, Catalyst, Raw oil, unsaturation