Hexane solvent extraction has long been used effectively for vegetable oil extrac­tion. A very good example is in the production of soybean oil, for which hex­ane solvent extraction is predominantly used in industrial production due to its lower energy consumption and higher extraction efficiency (oil yield) in comparison to hydraulic presses, that is, the expeller method. Furthermore, hexane extraction technology can be used as a stand-alone process for algae oil extraction or it can be used in conjunction with the physical extraction technology of the oil press/expeller method.

If a chemical extraction process based on cyclohexane as a chemical solvent is employed for algae oil extraction in conjunction with an expeller method, the envisioned process scheme is as follows.

The algae oil and lipids are first extracted using an expeller. The remaining pulp and biomass are then mixed with cyclohexane to extract the residual oil content remaining in the residue. The algae oil dissolves in cyclohexane, whereas the pulp and residues do not. The biomass is filtered out from the solution, and the biomass rejected here can be used for other energy gen­eration processes such as gasification. As the last stage, the algae oil and cyclohexane are separated by distillation. This two-stage extraction process of combined cold expeller press and hexane solvent extraction is capable of achieving an extraction efficiency of higher than 95% of the total oil present in the algae [35].