Energy Efficient Process for Solvent Extraction of Oil from Microalgae using Green Solvents

Solvent extraction by hexane is the most common choice for extraction of oil/lipids from algae. However, hexane is not the best choice of solvent for algae oil extraction because of the need to market byproducts for human and animal consumption. Oil and hexane from the solvent extraction process are separated by distillation/evaporation which is an energy intensive operation. Presence of explosive hexane vapors in the oil processing plant is also a serious safety concern. Extraction of algae oil with alcohols (e.g. ethanol) will eliminate the emission and toxicity issues. However, energy consumption for alcohol recovery/separation is significantly high because alcohols boil at higher temperature and latent heat of alcohols is 2-2.5 times higher than hexane. Compact Membrane Systems will develop energy efficient membrane separation process for separation of alcohol and oil from the solvent - algae oil extraction process. Algae oil extraction by alcohols (e.g. ethanol) will allow human and animal consumption of the byproducts. In addition, membrane separation process is a highly energy efficient technology compared to distillation/evaporation. Preliminary lab and economic evaluations suggest that our novel membrane technology is superior to existing commercial technologies. Commercial Applications and Other Benefits: Benefits of developing the proposed membrane technology come from energy and capital savings by replacing the conventional technologies such as distillation and evaporation. If successful at developing these membranes with superior solvent flux, oil retention, and thermal and chemical stability, it will have significant impact related to energy savings in many of the industrial processes using distillation and evaporation.