Flying high with algae

Results for their collaborative work have been published online in the prestigious international journal Energy & Environmental Science.

Professor Rocky de Nys from the Centre for Macroalgal Resources & Biotechnology

at James Cook University led the group responsible for providing the project with the fresh water algae. He said the algae was grown under special conditions and tailor-made to fit the needs of the project.

“Oedogonium is a robust, non-invasive species that is highly productive and easily cultivated on a large scale. This makes the macroalgae an attractive source of biomass for further processing to create renewable fuels and chemicals.

“Its cultivation is highly efficient relative to harvesting of land-based plants and also avoids conflict for agricultural resources that might be diverted from food production.”

Joint leaders at the University of Sydney, Dr Thomas Maschmeyer, Professor of Chemistry, and Professor Brian Haynes from the University’s School of Chemical and Biomolecular Engineering worked with their teams to understand how to control the conversion of freshwater algae into a crude oil equivalent.

“A key problem associated with processing algae into liquid transportation fuel is the presence of nitrogen from algal proteins in the intermediate bio crude oil, as the nitrogen poisons downstream catalysts required for further upgrading,” said Professor Maschmeyer.

“However the nitrogen content can, in fact, be controlled at multiple points in the production chain from biomass to high-grade fuel product,” said Professor Maschmeyer, who is also the Director of the Australian Institute for Nanoscale Science and Technology.

Explaining the process Professor Brian Haynes said:

“In order to utilise a macroalgal species effectively, its production needed to be integrated into a chain that addressed the issues of waste nutrient, water and carbon recycling.

“The low nitrogen macroalgae are converted to bio-crude oil, which is combined with a synthetic fuel stream produced by catalytic conversion of waste CO₂, resulting, after further processing, in a finished fuel blend.

“The process makes use of water at very high temperature and pressure to liquefy the algae and convert it into an energy-dense bio-crude oil.”

“Our research colleagues at Ben Gurion University used their expertise to take the bio-crude oil and refine it into a finished fuel product,” said Professor Haynes.

The work was supported in Australia by the Science and Industry Endowment Fund, the Australian Renewable Energy Agency (ARENA); the Advanced Manufacturing CRC (AMCRC), and MBD Energy Ltd.