Download - BioDiesel from Algae
Oil Extraction
By:Kyle Fricker
Background InformationAcre-by-acre microalgae can produce 30-100
times the oil yield of soybeans for biodiesel production
Algae can grow on marginal land and in brackish water
The biomass left-over from oil-pressing can either be fed to cattle as a protein supplement, or fermented into ethanol (and possibly recycled into the biodiesel refining process)
SonicationIdea: Send ultrasonic sound waves through
algae/water solution, break algal cell walls, let oil collect at the top of the liquid and skim off
Currently used in ponds to kill off troublesome algae
Positive: environmentally benign, relatively low cost
Negative: not effective yet, most internet sources claim using ultrasound along with other methods – microwaves, solvents, mechanical presses
Mechanical PressMortar and pestle (not very economical)Screw Press – numerous online sources claim to
use this method with average yieldsMust be sized quite small since algal cells are
microscopicDutch company, AlgeaLink, sells screw presses along
with photo reactors for growing the algae. They allege to yielding 50% oil by mass, but the cheapest press costs € 7300
Most industrial processes mechanically press, then treat the sludge with a solvent to extract the oil that remains
Osmotic ShockGrow algae in high saline solution and
harvest into a sludgeAfter dumping the sludge into distilled water,
the cells theoretically will burst with the mass exodus of salts
Oil can then be skimmed off the surfaceI did not find any experimentation on this
method, yet the theory makes sense and experimentation is relatively easy
Freezing & Deconstructive DecompressionIs it possible to freeze
and thaw a batch of algae to break the cell wall?
When they are frozen, the cells will expand
Once allowed to thaw, the change in size could rupture cell walls allowing for the lipids to be released
Similarly, if algae were compressed and rapidly decompressed, would the force on the cells be too much to handle?
Not much, if any, research has been done on these ideas – yet they are easy experiments to perform
Solvent ExtractionWidely used, high yieldsExpensive; deal with nasty chemicalsUsually used in conjunction with
other extraction techniques
The PlanIt seems the best yields and time
consumption can be achieved by combining a few of the aforementioned
I will be looking into sonication, freezing, deconstructive decompression, and possibly osmotic shock
Results will be viewed under a light microscope
Algae-to-BioFuelThis stuff is actually happeningPetroSun has a commercial
algae-to-biofuel plant insouthern Texas that opened in April 2008.
Here’s a picture of the facility taken from Google Earth
Fossil Fuel is Fossil Thinking