Six hydrothermal liquefaction experiments on Nannochloropsis salina and Spirulina platensis at subcritical and supercritical water conditions (220-375 °C, 20-255 bar) were carried out to explore the feasibility of extracting lipids from wet algae, preserving nutrients in lipid-extracted algae solid residue, and recycling process water for algae cultivation. GC-MS, elemental analyzer, FT-IR, calorimeter and nutrient analysis were used to analyze bio-crude, lipid-extracted algae and water samples produced in the hydrothermal liquefaction process. The highest bio-crude yield of 46% was obtained on Nannochloropsis salina at 350 °C and 175 bar. For Spirulina platensis algae sample, the optimal hydrothermal liquefaction condition appears to be at 310 °C and 115 bar, while the optimal condition for Nannochloropsis salina is at 350 °C and 175 bar. Preliminary data also indicate that a lipid-extracted algae solid residue sample obtained in the hydrothermal liquefaction process contains a high level of proteins.
- Hydrothermal liquefaction
- Subcritical water
- Algal biofuel
- Nannochloropsis salina
Toor, S., Reddy, H., Deng, S., Hoffmann, J., Spangsmark, D., Madsen, L. B., Holm-Nielsen, J. B., & Rosendahl, L. (2013). Hydrothermal liquefaction of Spirulina and Nannochloropsis Salina under subcritical and supercritical water conditions. Bioresource Technology, 131, 413-419. https://doi.org/10.1016/j.biortech.2012.12.144