Purification of Biodiesel Generated by Transesterification of Oil Extracted From Algal Biomass: A Review

This paper reviews the status freshwater algae as source of biodiesel production. Chlorella vulgaris, Rhizoclonium hieroglyphicum and mixed algae culture (Microspora sp., Navicula sp., Lyngbya sp., Cladophora sp., Spirogyra sp. and Rhizoclonium sp.) were used with the objective of biodiesel production from harvested biomass of algae. Oil was extracted from dried biomass. Biodiesel was synthesized from algal oil using various catalysts (Na, NaOH, KOH & H2SO4) and its properties such as density, kinematic viscosity, flash point, specific gravity, cetain number, acid number, water contents and calorific value were analyzed. Biodiesel production from algal oil showed maximum production (93.93%) by C. vulgaris. Comparison of catalysts in terms of biodiesel yield from dried algal biomass showed maximum yield (48.2%) with 1.5% concentration of Na metal catalyst in reaction time of 60 minutes. Quality analysis of biodiesel showed that good quality biodiesel was synthesized in the presence of Na metal catalyst with following characteristics; density (0.87 kg/l) kinematic viscosity (5.2 mm2/s), flash point (145 °C), specific gravity (0.916 g/ml), cetain number (53 min), acid number (0.37 mg.KOH/g), water contents (0.04 %vol) and calorific value (41.2 MJ/Kg). Comparison of various feedstocks of biodiesel showed less land use and more oil production with microalgae.