Researchers find way to turn algae into fuel

Biofuel experts have been working to find an economically-viable way to turn algae into biocrude oil to power various types of vehicles. An unusually rapid method to deliver biocrude oil in large quantities has been developed using a specially-designed jet mixer.

According to the research published by University of Utah in Chemical Engineering Science X, the chemical engineers have developed a new kind of jet mixer that extracts the lipids with much less energy than the older extraction method. It is a key discovery that now, puts this form of energy closer to becoming a viable, cost-effective alternative fuel.

Packed inside the microorganisms growing in ponds, lakes and rivers are lipids, which are fatty acid molecules containing oil that can be extracted to power diesel engines. When extracted, the lipids are called biocrude. That makes organisms such as microalgae an attractive form of biomass, organic matter that can be used as a sustainable fuel source.

These lipids are also found in a variety of other single-cell organisms such as yeasts used in cheese processing. But the problem with using algae for biomass has always been the amount of energy it takes to pull the lipids or biocrude from the watery plants. Under current methods, it takes more energy to turn algae into biocrude than the amount of energy you get back out of it.

Right now, in order to extract the oil-rich lipids from the algae, scientists have to pull the water from the algae first, leaving either a slurry or dry powder of the biomass. That is the most energy-intensive part of the process. That residue is then mixed with a solvent where the lipids are separated from the biomass. What's left is a precursor, the biocrude, used to produce algae-based biofuel.

However, this requires so much energy to extract the water from the plants at the beginning of the process, turning algae into biofuel has thus far not been a practical, efficient or economical process.

“The team has created a new mixing extractor, a reactor that shoots jets of the solvent at jets of algae, creating a localized turbulence in which the lipids jump a short distance into the stream of solvent. The solvent then is taken out and can be recycled to be used again in the process, and this technology could also be applied to a variety of microorganisms such as bacteria, and fungi” said Swomitra ‘Bobby’ Mohanty, a co-author on the paper.

This technology could also be applied beyond algae and include a variety of microorganisms such as bacteria, fungi, or any microbial-derived oil, Mohanty added.