Department: 
Food Science & Technology
Project manager(s): 
Year: 
2019

Nowadays, production of biodiesel from micro-alga biomass has been progressively attentioned due to decreasing of fossil energy resources and the need to develop alternative renewable sources. Most of the conventional methods for biofuel production are energy-intensive and require the use of toxic solvents. Currently, a new method of oil extraction from biomass based on subcritical water technology is being developed. In this method, drying the biomass which is energy intensive process, is removed and water as a green solvent is used under subcritical condition (at 100 ° C to 374 ° C under pressure). In this research, oil extraction from microalgae was carried out by using of pure water and mixture of water and ethanol as subcritical solvents in different operating conditions; then mathematical modeling was performed and verified by experimental results. Ultimately, the results were compared with Soxhlet, ultrasonic and Folch, well-known extraction methods. Results indicated that extraction performance in subcritical water method (29.35 % wt.  at 200 °C, flow rate 4ml/min and loading of Microalgae 1 g) was extremely higher than Soxhlet (7.01%) and ultrasonic (5.03%) methods, and near the extraction performance of Folch method (25.36%). Despite of decrease of extraction temperature to 90 °C, efficiency was increased to 33.93% by adding ethanol to water (up to 75% wt.). This was due to reducing of solvent polarity. In conclusion, these results show that subcritical solvent extraction method can be used successfully for oil extraction from biomass