Making eco-friendly fuel from algae has moved one step closer to becoming a reality, thanks to a team of researchers from Sheffield University.
Algae contain oil that can be extracted by a number of different techniques, ranging from pressing to using chemical solvents.
But, producing algae in sufficient quantities and separating them from the water they grow in had proved too expensive until Professor Will Zimmerman and his team from Sheffield University’s Department of Chemical and Biological Engineering came up with a solution.
The team began by carrying out award-winning research to develop a way of generating microbubbles – bubbles smaller than one millimetre in diameter – as a means of growing algae more rapidly and densely.
Prof Zimmerman said: “We thought we had solved the major barrier to biofuel companies processing algae to use as fuel when we used microbubbles to grow the algae more densely.
“It turned out, however, that algae biofuels still couldn’t be produced economically, because of the difficulty in harvesting and de-watering the algae.
“We had to develop a solution to this problem and again, microbubbles provided a solution.”
The team uses more microbubbles to bring algae particles to the surface of the water and keep them floating there, making harvesting easier and saving biofuel-producing companies time and money.
Microbubbles have been used by water purification companies to float out impurities, but have not been used to separate algae from water before because previous methods were very expensive.
The system developed by Prof Zimmerman’s team uses up to 1,000 times less energy to produce the microbubbles and is predicted to cost much less than existing flotation systems.
Now, the team wants to develop a pilot plant to test the system on an industrial scale.
Prof Zimmerman is already working with Tata Steel at the firm’s Scunthorpe site, using CO2 from flue-gas stacks to test the new system.