Optimization of Biodiesel Production Process from Household Waste Oil, Rapeseed, and Microalgae Oils as a Suitable Alternative for Jet Fuel

In this study, the possibility of replacing non-renewable jet engine fuels with biodiesel produced from household waste oils, rapeseed, and Neochloris overabundance microalgae was investigated. To optimize biodiesel production, firstly, the effect of 4 parameters of oil-to-methanol molar ratio, catalyst weight percentage, temperature, and process time in three levels for household waste and rapeseed oil were investigated using the Taguchi method. The biodiesel production efficiency under the optimal conditions of 1 (w/v)% catalyst, the molar ratio of oil to methanol 1:8 at 65℃ for 80 min for waste oil and 40 min for rapeseed oil was 85.83% and 72.7%, respectively. Then, under the optimal conditions (1.1 (w/v/)% catalyst percentage, 1:8 molar ratio of oil to methanol at 65℃) obtained by investigating the effect of catalyst percentage and process time as the most impressive parameters on microalgae oil transesterification at three levels by the response surface method, the biodiesel production efficiency of microalgae oil was 86.25%. Gas chromatography–mass spectroscopy (GC–MS) analysis of samples showed a transesterification reaction efficiency of more than 96%. Combustion and qualitative analysis such as flash point, cloud point, pour point, freezing point, viscosity, density, and specific gravity on the produced biodiesels showed that all three biodiesel have the same performance as Jp-4 jet fuel without deposits. Also, microalgae oil biodiesel with a flash point of 188℃, cloud point of 3℃, pour point of 8℃, a viscosity of 4.5 mm2/s, a density of 0.882 g/mL, and specific gravity 0.882, calorific value 40.2 (Mj/Kg) had the best performance.