Ok... So let's say that I have a friend that lives near a bunch of brown algae (kelp), and has a giant veggie van for transporting kelp to a sunny spot to dry. Is it feasible to dry this kelp, press it, centrifuge the resultant oil, and burn it in his mercedes and E350 van?
Or does algae produced oil need to be converted to biodiesel?

Anyone?

I don't know if you would get much oil out of this material, but the oil extracted from the strains used for biodiesel are actually lighter oils, much like sunflower for example, containing shorter carbon chains. So algae oil should work well in SVO conversions.

One company trying to do this commercially in Seattle WA is Blue Marble Energy .

This message has been edited. Last edited by: clean and green,

I've heard that ~30lbs of kelp yields about 2 gallons of oil...

I'm sure folks doing it are keeping their mouths shut for the most part.

I don't know about oil in kelp, but to extract the oil from algae took a lot more than pressing. Here's the processes used by one of my professors when they grew a variety of algae strains in the exhaust from a coal power plant: First, concentrate the algae (the cells are so small they doesn't "filter" easily, and you have to dewater it somehow to reduce the volume you're working with. Kelp would be easier.) Ultrasonics were used to rupture the cells. The lipids float, the junk sinks. "Lipids" sounds like nice clean, pure oil, but it isn't. It's a combination of liquid substances that is up to 40% oil, in this case, and higher in other reports. The oil itself is a combination of different tryglycerides, just like vegetable oils.

My prof didn't try to separate the oil from the rest of the lipid liquids. He just analyzed them. From 100cc sample of water, containing about 1cc algae, he got about 0.1-0.2cc lipids, of which 0.04-0.08cc was "oil". That's a ratio of 2500:1, to 1250:1. That's a lot of liquid to handle for a little oil, and that's the problem. Imagine a 2500 gallon tank of liquid (water with algae grown in it) that contains 1 gallon of fuel. You've got to eliminate 2499 gallons of water and goo to get the oil. The oil is only feestock, needing more work before it's biodiesel. It makes no sense unless there's a market for all the rest of the co-products created.

Different strains of algae produce different combinations of triglycerides, and also have different substances in the cells that confound the accessability to the oil. This is the key to answering the question. There are some algaes that might produce diesel-like oils, not needing to be transesterfied, but I have no experience with those.

I was surprised to learn that algae are up to 40% carbohydrates, mostly sugars. They can be fermented into alcohol much easier and with higher yield than oil. Fermentation is a "wet" process that doesn't require drying, which saves enormous process energy. This also converts the residue into high protein meal, which has higher food value than the goo created when oil is extracted. It might be worth investigating kelp for fermentation potential.

Algae can be dried and burned as a solid fuel. It releases more energy that way than if it's converted into oil, ethanol, or anything else. It has the potential to replace other solid fuels, like coal, but the acreage required to supply a single coal plant is enormous. Not completely impractical, just big, and therefore expensive enough to look at other options first. Like covering the same area with solar panels.

Cheers,
JohnO