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BioDiesel from Algae. Oil Extraction. By: Kyle Fricker. Background Information. Acre-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
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BioDiesel from Algae Oil Extraction By: Kyle Fricker
Background Information • Acre-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)
Sonication • Idea: 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 Press • Mortar and pestle (not very economical) • Screw Press – numerous online sources claim to use this method with average yields • Must be sized quite small since algal cells are microscopic • Dutch 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 Shock • Grow algae in high saline solution and harvest into a sludge • After dumping the sludge into distilled water, the cells theoretically will burst with the mass exodus of salts • Oil can then be skimmed off the surface • I did not find any experimentation on this method, yet the theory makes sense and experimentation is relatively easy
Freezing & Deconstructive Decompression • Is 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 Extraction • Widely used, high yields • Expensive; deal with nasty chemicals • Usually used in conjunction with other extraction techniques
The Plan • It 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-BioFuel • This stuff is actually happening • PetroSun has a commercial algae-to-biofuel plant in southern Texas that opened in April 2008. • Here’s a picture of the facility taken from Google Earth