Optimization of biodiesel production process from household waste oil, rapeseed, and microalgae oils as a suitable alternative for jet-fuel

Abstract

In this study, to investigate the possibility of replacing non-renewable jet engines with biodiesel produced from household waste oils, rapeseed, and Neochloris oleobundance microalgae, biodiesel was first produced by two-stage transesterification using methanol, alkaline and acidic catalysts of potassium hydroxide and sulfuric acid, and then were compared to jet fuel quantitatively and qualitatively. To optimize the biodiesel production, first, the effect of 4 parameters of oil-to-methanol molar ratio, catalyst weight percentage, temperature, and process time at three levels for household waste and rapeseed oils was investigated by Taguchi method. Then, under the obtained optimal conditions, the effect of catalyst weight percentage and process time as the most impressive parameters were examined at three levels on microalgae oil transesterification by response surface method. The biodiesel production efficiency under optimal conditions of all three samples of waste oils was 85.83%, rapeseed 72.7%, and microalgae 86.25%, which is one of the highest values reported. Analysis of all samples by GC-Mass and evaluation of the final results of the transesterification reaction efficiency was over 96%. Combustion analyzes of calorimeter bombs and qualitative specifications analyses such as flash point, cloud point, pour point, freezing point, viscosity, density, and specific gravity were performed on the produced biodiesels to investigate the effects of biodiesel on engine performance. Results Analysis showed that all three biodiesel samples have the same performance as Jp-4 jet fuel and can use it as jet fuel without any sediment. In addition, the biodiesel produced from microalgae oil had the best performance and efficiency.