Heating and squishing microalgae in a pressure cooker may be a new and quicker method for producing bio-oil from the organism.
Researchers from the University of Michigan say that the new method of processing the fuel source ‘can fast-forward the crude-oil-making process from millennia to minutes.’
University of Michigan professors are working to understand and improve this procedure in an effort to speed up development of affordable biofuels that could replace fossil fuels and power today’s engines. Algae has been mooted as an ideal fuel solution as unlike traditional biofuel production-it doesn’t interfere with food production.
They are also examining the possibility of other new fuel sources such as E. coli bacteria that would feed on waste products from previous bio-oil batches.
The new method is quicker than the current method of algae-based oil production which relies on the process of drying first before the algae oil can be extracted. The old method relied upon selecting the most oil-rich algae whereas the new method can make use of lower quality algae too while also removing the need for the time-sapping drying step.
"We make an algae soup," Phillip Savage, Professor in the University’s Department of Chemical Engineering explained.
"We heat it to about 300 degrees and keep the water at high enough pressure to keep it liquid as opposed to steam. We cook it for 30 minutes to an hour and we get a crude bio-oil."
The high temperature and pressure allows the algae to react with the water and break down. Not only does the native oil get released, but proteins and carbohydrates also decompose and add to the fuel yield.
"We’re trying to do what nature does when it creates oil, but we don’t want to wait millions of years," Savage said. "The hard part is taking the tar that comes out of the pressure cooker and turning it into something you could put in your car, changing the properties so it can flow more easily, and doing it in a way that’s affordable."
Unlike fossil fuels, algae-based biofuels are carbon-neutral. The algae feed on carbon dioxide in the air, and this gets released when the biofuel is burned. Fossil fuel combustion releases stored carbon dioxide into the air without ever taking any back.
Savage and his colleagues will continue their research, now hoping to investigate ways to use catalysts to bump up the energy density of the resulting bio-oil, thin it into a flowing material and also clean it up by reducing its sulfur and nitrogen content.
Furthermore, they’re examining the process from a life-cycle perspective, seeking to recycle waste products to grow new source material for future fuel batches. “This doesn’t have to be algae,” Savage said. It could be any "wet biomass." They are working on growing in their experiments’ waste products E. coli that they could potentially use along with algae.
A $2million National Science Foundation grant supported the project as part of the United States focus on developing biofuel solutions.
