edthecynic
Censored for Cynicism
- Oct 20, 2008
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Biodiesel is diesel fuel, Oh wait, everyone knows how diesel fuel works in a diesel automobile engine.Cultivating Algae for Liquid Fuel Production
GreenFuel bioreactor in field test
GreenFuel Technologies in Cambridge, MA is field testing a closed system that uses the CO2 in power plant flue gases (13% of flue gases in the test) to feed algae. (3,4) In so doing, it significantly reduced the CO2 concentration in the exhaust by 82.3% (+/-12.5%) on sunny days and by 50.1% (+/- 6.5%) on cloudy days during the beta-test at the Cogeneration Plant at MIT. (5) The process also removed 85.9% (+/- 2.1%) of nitrogen oxides. And, not only will the GreenFuel Bioreactors reduce carbon and NOx emissions, but the company estimates the cost of a full-scale system installation to be 20% to 40% less than that of a comparable SCR system (pollutant scrubbers).
Using technology licensed from a NASA project, GreenFuel constructs triangular-shaped bioreactors from polycarbonate tubing two to three meters long and 10-20 cm in diameter. The hypotenuse of the triangles face the sun. Flue gases are introduced at the bottom of the hypotenuse and flow up while the media containing the algae flow in the opposite direction. From 15% to 30% of the algal media are harvested each day. The use of tubes in which to grow the algae overcomes the usual surface area limitation of ponds. In this case the turbulent mixing of the algal media with CO2 in the tubes and the speed at which the fluid moves determine how fast the algae grow.
"Until now, it was proving that the technology works. Now, basically, it's proving that the economics behind the technology work," said Isaac Berzin, chief technology officer. "The idea behind all this is that it's not a charity. If it makes sense econo*mically, it will happen." "I read descriptions of all this (previous) research, and it was clear to me that the limiting factor was the engineering side of the system," he said. "Algae can take (carbon dioxide), eat it, and produce algae, that's a known fact. But if your system fails, it's a problem with the system, not the algae."
A GreenFuel Technologies bioreactor in operation. Photos courtesy GreenFuel Technologies.
GreenFuel estimates that 70% of the power plants in the United States have enough space and 'food' to install a full complement of Bioreactor arrays. In the United States about 60% of the oil we use is for ground transportation—cars, vans, and trucks—while only about 25% is used as electricity. Potentially this means that GreenFuel reactors might be able to provide 20*-25% of the fuel needed to meet our transportation needs.
The GreenFuel Bioreactors could be used to fuel the power plant from which the algae are being fed. So you could build a power plant—including the reactors—and only have to provide it with enough fuel to get the bioreactors going! These reactors could also be used in breweries, fed from the excess CO2 that most breweries just waste.
Wonderful.....Now we wait for marketing and distribution.....Oh wait. No one knows yet how this stuff will work in an automobile engine.
And with the billions in research and development, the cost of pond scum fuel will be unaffordable.
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