A solution to the difficult issue of harvesting algae for
use as a biofuel has been developed using microbubble technology pioneered at
the University of
Sheffield. The technique
builds on previous research in which microbubbles were used to improve the way
algae is cultivated.
Algae
produce an oil which can be processed to create a useful biofuel. Biofuels,
made from plant material, are considered an important alternative to fossil
fuels and algae, in particular, has the potential to be a very efficient
biofuel producer. Until now, however, there has been no cost-effective method
of harvesting and removing the water from the algae for it to be processed
effectively.
Now, a team
led by Professor Will Zimmerman in the Department of Chemical and Biological
Engineering at the University
of Sheffield, believe
they have solved the problem. They have developed an inexpensive way of
producing microbubbles that can float algae particles to the surface of the
water, making harvesting easier, and saving biofuel-producing companies time
and money. The research is published in Biotechnology
and Bioengineering.
Zimmerman
and his team won the Moulton Medal, from the Institute of Chemical
Engineers, for their earlier work which used the
microbubble technology to improve algae production methods, allowing producers
to grow crops more rapidly and more densely.
"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,"
explains Zimmerman.
"It
turned out, however, that algae biofuels still couldn´t be produced
economically, because of the difficulty in harvesting and dewatering the algae.
We had to develop a solution to this problem and once again, microbubbles
provided a solution."
Microbubbles
have been used for flotation before: water purification companies use the
process to float out impurities, but it hasn´t been done in this context,
partly because previous methods have been very expensive.
The system developed
by Zimmerman´s team uses up to 1000 times less energy to produce the
microbubbles and, in addition, the cost of installing the Sheffield
microbubble system is predicted to be much less than existing flotation
systems.
The next
step in the project is to develop a pilot plant to test the system at an
industrial scale. Professor Zimmerman is already working with Tata Steel at
their site in Scunthorpe using carbon dioxide
from their flue-gas stacks and plans to continue this partnership to test the
new system.
SOURCE
