Extraction of microalgae oil and further production for second-generation biodiesel

To efficiently convert the microalgae to valuable and renewable fuels, the microalgae oil was first extracted and then transformed into the second-generation biodiesel. Among all solvents that were used for the microalgae oil extraction, the polar single solvent system methanol achieved the optimal value (47.8% extraction yield) because the polar cell membrane was easily dissolved by the polar solvent. Hexadecanoic acid (38.54%) and docosanoic acid (54.39%) dominated in fatty acid of microalgae oil. In the catalytic deoxygenation of microalgae oil, the Co-Al nanosheet displayed a higher performance than Co/Al2O3 because of its high Co content and lamellar structure, exposing massive Co sites with high dispersion and small particle size. Moreover, when the reaction temperature was raised to 240 degrees C, the 100% conversion and 100% alkane yield were obtained, and the further temperature rise in temperature led to the cracking reaction.