Putting the pressure on algae to create biofuel
Peigao Duan, a University of Michigan graduate student, holds a vial of bio-oil
If you’ve read even a little bit about potential sources of biofuel, you’ll know that algae is one of the big ones. During photosynthesis, this unicellular aquatic plant turns sunlight and carbon dioxide into oil. It’s grown in ponds, where it’s not taking land away from food production, and yields much more oil than other biofuel crops, such as corn or soybeans. Researchers at the University of Michigan have recently come up with a method of getting algae to give up its oil more quickly and efficiently than has previously been possible - they pressure cook it.
The current method of creating algae fuel involves cultivating special oily types of algae, drying them out, then extracting their oil. UM’s method allows the use of regular, less-oily algae, which is added to water. The algae-water is heated to 300 degrees, and kept at a high enough pressure that it remains liquid instead of turning to steam. The high pressure and temperature cause the algae to react with the water and break down, plus they cause the algae’s proteins and carbohydrates to rapidly decompose. The result of both reactions, after 30 to 60 minutes, is crude bio-oil.
It’s the same basic process that created fossil fuels from prehistoric plants, only UM’s method takes minutes instead of millennia.
Presently, the oil has a tar-like consistency. The researchers looking at ways of making it flow better, along with the possible use of catalysts to increase its energy-density, and the reduction of its sulfur and nitrogen content to make it cleaner.
About the Author
An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.
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So what is the energy exchange? How much energy do you have to put in, or more importantly how much energy do you net?
The energy balance may not necessarily be that bad. 140C is low grade heat. You could possibly have it as a waste heat from some other industrial processes.
The procedure reminds me of Changing World Technologies: they cook waste turkey offal to produce bio diesel. They run against serious problems though: smell of their operation necessitated expensive air scrubbers, they did not get waste offal for free and they run up against changing composition of their waste. You need the same composition to get the optimum results. They though of outsourcing further refinery process to regular oil refineries after doing their cooking.
Bio ethanol companies did their best to kill a potential competition. (They succeeded.)
Algae are obviously not free. But their composition may be more stable/predicable. Smell should not be that much of an issue.
Gizmag likely have blundered about the temperature. At Michigan edu linked videos they speak about \"three times the temperature of boiling water\". This is obviously NOT 300F but rather 300C. This is not low grade heat by any stretch. It is serious heat.
Ed note: indeed it seems we did, The press release simply states "300 degrees". The article has been amended. Thanks for the feedback - getting it right is our number one priority.
Hydrogen is the future Energy Carrier. Algae comes handy for hydrogen production.
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