how do you extract oil from algae ?

Well been reading that algae is a renewable fuel but I can't see how ? So how do you get the oil that is discussed out of the algae? Is it one of these non sustainable horribly expensive and hideous to the environment jobbies that we are told will save the world?

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Kiteman8 years ago
Oil is extracted from all sorts of plants, especially their seeds, so there is no reason why it can't be usefully extracted from algae.

The main methods are:
  • Pressing (simply squeezing the oil out, like a high-pressure cider press).
  • Solvent extraction (more efficient, but not so "green", since it often uses benzene)
  • "Supercritical" extraction - this is still solvent extraction, but the solvent is liquified CO2 - this is the most efficient method, but uses the most specialised equipment.
strangebike (author)  Kiteman8 years ago
Thank you fella I am now a whole heap closer to understanding what this fuel could be used for. So it would be a vegetable oil so for diesel engines then?
Probably, although there are plans afoot to fly commercial jets on an algae-oil / kerosene blend.
zaronas Kiteman5 years ago
they have actually flown an airplane up to 17,000 feet on 100% bio diesel and it lew just fine
Kiteman zaronas5 years ago
(You'll note there's 3½ years between our posts.)

Have you got a link?
zaronas Kiteman5 years ago
yah i tend to forget to look at the date of the post but yah
Kiteman zaronas5 years ago
At the moment the most efficient way to extract oil from algae is to dry it and press it in a screw or extrusion press. A good design for a simple manual screw press can be found on any number of places. Dried algae can also be used as livestock feed. Studies have shown that 10-25% of barley or alfalfa feed may be safely substituted with algae. If you're planning on making bio-diesel you'll want to check out Mother Earth News Ethanol. There's some interesting studies there on producing 200 proof ethanol (algae biodiesel is made with sodium ethylate rather than methyl hydroxide). It is easy to obtain a Small Fuel Producers License from the ATF to operate a legal still. Once you've got the 200 proof ethanol you can make ethylate by (carefully) mixing the ethanol with sodium. This is the catalyst for the biodiesel production. You'll also need saltwater and ether (which can be produced by the interaction of ethanol and sodium hydroxide lye) to seperate out the biodiesel.
jtobako Kiteman8 years ago
You may need to dry the algae to press oil out, or break up the cells (chemically or physically-like with a blender) and then centrifuge the oil to the surface.

Distillation (probably from dry stocks) might be another process.

OOps, wikipedia to the rescue : o