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EO – 208 BIOFUEL. BIODIESEL FROM ALGAE. Alga – a photosynthetic organism of a group that lives mainly in water and that includes seaweeds. Algae facts Algae are made up of prokaryatic as well as eukaryotic cells. These are cells with nuclei and organelles.
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EO – 208 BIOFUEL BIODIESEL FROM ALGAE
Alga– a photosynthetic organism of a group that lives mainly in water and that includes seaweeds.
Algae facts • Algae are made up of prokaryatic as well as eukaryotic cells. These are cells with nuclei and organelles. • All algae have plastids, the bodies with chlorophyll that carry out photosynthesis. • Various lines of algae have different combinations of chlorophyll molecules. Some have only Chlorophyll A, some A and B, while other lines, A and C. • All algae have the following: Proteins, Carbohydrates, Fats and Nucleic Acids. • Algae can have up to 40% of their overall mass be fatty acids. It is this fatty acid (oil) that can be extracted and converted into biodiesel.
Algae facts • Grows naturally all over the world. • Comes in various forms and color, from tiny protozoa floating in ponds to huge bunches of seaweed inhabiting the ocean. • There are more than 100,000 different species of plant-like organisms in the algae family. • There are about 2,000 reported species of nitrogen-fixing algae. • About 1,000 species are found in fresh water.
Algae facts • Algae is easy to please - all they need are water, sunlight, and carbon dioxide. • Algae can be manipulated to produce huge amounts without disturbing any natural habitats or food sources. • Acre by acre, microalgae can produce 30 -100 times the oil yield of soybeans on marginal land. • Half of algae’s composition, by weight, is lipid oil.
Lipids - the trick is to produce microalgae species that can accumulate lipids under nutrient depleted circumstances
Biodiesel • Considered a renewable substitute for diesel produced from fossil fuels. • Various natural oils, fats, and greased can be converted into biodiesel. • Biodiesel can help reduce the levels of greenhouse gases. • Biodiesel removes carbon from the air, resulting in lowering pollution. • Several species of algae have been studied for their ability to produce natural oils that can be converted to natural fuel
Out of all the algae out there, pond scum (algae that sits on the top of ponds) is best suited for biodiesel.
Through photosynthesis, algae pulls carbon dioxide from the air, replacing it with oxygen.
Biodiesel from algae facts • a 100-acre algae biodiesel plant could potentially produce 10 million gallons of biodiesel in a single year • Experts estimate it will take 140 billion gallons of algae biodiesel to replace petroleum-based products each year. • To reach this goal, algae biodiesel companies will only need about 95 million acres of land to build biodiesel plants, compared to billions of acres for other biodiesel products. • The real question, and one which many companies all over the globe are trying to answer, is how can we produce enough to meet the demand for biodiesel?
Biodiesel makers claim they'll be able to produce more than 100,000 gallons of algae oil per acre per year depending on: • The type of algae being used • The way the algae is grown
The method of oil extraction • Oil press is the simplest and most popular method. It's similar to the concept of the olive press. It can extract up to 75 percent of the oil from the algae being pressed. • The hexane solvent method (combined with pressing the algae) extracts up to 95 percent of oil from algae. First, the press squeezes out the oil. Then, leftover algae is mixed with hexane, filtered and cleaned so there's no chemical left in the oil. • The supercritical fluids method extracts up to 100 percent of the oil from algae.
Supercritical fluids method • Carbon dioxide acts as the supercritical fluid -- a substance is pressurized and heated to change its composition into a liquid as well as a gas. • Carbon dioxide is mixed with the algae. • When they're combined, the carbon dioxide turns the algae completely into oil. • The additional equipment and work make this method a less popular option.
Once the oil's extracted, it's refined using fatty acid chains in a process called transesterification. • Chemically, transesterification means taking a triglyceride molecule or a complex fatty acid, neutralizing the free fatty acids, removing the glycerin and creating an alcohol ester. • This is accomplished by mixing methanol with sodium hydroxide to make sodium methoxide. This liquid is then mixed into vegetable oil. The entire mixture then settles. Glycerin is left on the bottom and methyl esters, or biodiesel, is left on top. • The glycerin can be used to make soap (or any one of 1600 other products) and the methyl esters is washed and filtered. • Transesterification of algal oil is normally done with Ethanol and sodium ethanolate serving as the catalyst. • With sodium ethanolate as the catalyst, ethanol is reacted with the algal oil ( the triglyceride) to produce bio-diesel & glycerol. The end products of this reaction is biodiesel, sodium ethanolate and glycerol. • Biodiesel is in turn separated from ether by a vaporizer under a high vacuum. As the ether vaporizes first, the Biodiesel will remain.
There are several ways to grow algae open-pond or closed-pond systems
Open Pond • The most natural method of growing algae for biodiesel production. • Using open ponds, we can grow algae in hot, sunny areas of the world to get maximum production. • Open pond is the least invasive of all the growing techniques, but it has some drawbacks. • Bad weather can stunt algae growth, as can contamination from strains of bacteria or other outside organisms. • The water in which the algae grow also has to be kept at a certain temperature, which can be difficult to maintain.
Closed pond/Vertical growth • Has been developed by biofuel companies to produce algae faster and more efficiently than open pond growth. • With vertical growing, algae are placed in clear plastic bags, so they can be exposed to sunlight on two sides. • The bags are stacked high and protected from the rain by a cover. • The extra sun exposure increases the productivity rate of the algae, which in turn increases oil production. • The algae are also protected from contamination.
Instead of growing algae outside, indoor plants are built with large, round drums that grow algae under ideal conditions.
Closed-tank bioreactor • The algae are manipulated into growing at maximum levels and can be harvested every day. • This yields a very high output of algae, which in turn yields large amounts of oil for biodiesel. • Can also be strategically placed near energy plants to capture excess carbon dioxide that would otherwise pollute the air. • Algae are cultivated in closed containers and fed sugar to promote growth. • This method eliminates all margin of error since it allows growers to control all environmental factors. • Researchers are trying to figure out where to get enough sugar without creating problems. • The benefit of this process is that it allows the algae biodiesel to be produced anywhere in the world.
PetroSun will begin operation of its commercial algae-to-biofuels facility on April 1st, 2008. The facility, located in Rio Hondo Texas, will produce an estimated 4.4 million gallons of algal oil and 110 million lbs. of biomass per year off a series of saltwater ponds spanning 1,100 acres. Twenty of those acres will be reserved for the experimental production of a renewable JP8 jet-fuel.
