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