Algae Fuel

Algae are tiny biological factories that use photosynthesis to transform carbon dioxide and sunlight into energy so efficiently that they can double their weight several times a day. Algae oil is an interesting sustainable feedstock for biodiesel manufacturing. It is an alternative to popular feedstocks, like soybean, canola and palm. In comparison to traditional oil-seed crops, algae yields much more oil per acre. While soybean typically produces less than 50 gallon of oil per acre and rapeseed generates less than 130 gallon per acre, algae can yield up to 10,000 gallons per acre. In particular diatoms and green algae are good sources for the production of biodiesel.

History as Fuel

The idea of using algae as a source of food, feed and energy goes back more than half a century. Production of methane gas from algae was proposed in the early 1950s, and received a big impetus during the energy crisis of the 1970s, when projects were initiated to produce gaseous fuels (hydrogen and methane). From 1980 to 1996 the US Department of Energy supported the Aquatic Species Program (ASP), a relatively small effort (about $25 million over almost 20 years) with the specific goal of producing oil from microalgae.

So exactly how can we get oil from algae?

 Algae are grown in either open-pond or closed-pond systems. Once the algae are harvested, the lipids, or oils, are extracted from the walls of the algae cells.There are a few different ways to extract the oil from algae. The 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.

Basically a two-part process, 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. Carbon dioxide acts as the supercritical fluid . when a substance is pressurized and heated to change its composition into a liquid as well as a gas. At this point, 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. Here, a catalyst such as sodium hydroxide is mixed in with an alcohol such as methanol. This creates a biodiesel fuel combined with a glycerol. The mixture is refined to remove the glycerol. The final product is algae biodiesel fuel.The process of extracting oil from the algae is universal, but companies producing algae biodiesel are using diverse methods to grow enough algae to produce large amounts of oil.

Different Bio fuels made with algae

Biodiesel - Microalgae are involved in the production of biodiesel. Microalgae are chosen for the production of biofuel based on their oil content. The oil inside the microalgae is removed from algae by chemical means or either squeezed out. The oil is collected and changed chemically and is then used as an ingredient in biodiesel.

Bioethanol – Bioethanol is an ingredient used in the production of petrol. Macroalgae that contain a lot of sugar are chosen. Macroalgae are cut, mashed and treated.The macroalgae now appear as sludge and is called feedstock. Other micro-organisms called Yeast are added at this stage. Yeast uses the feedstock

as food and breaks down the feedstock into ethanol and other components. This process is called fermentation. Ethanol is separated from the other components and then the ethanol is used in petrol.

Biogas – Methane is the main ingredient in the production of biogas. Methane gas can be produced by using macroalgae. The macroalgae must have a high sugar content. Macroalgae are cut and mashed. Micro-organisms convert the natural sugars in macroalgae into glucose. The macroalgae now appear as sludge and is called feedstock. The feedstock will go into a big tank and special micro-organisms called anaerobes are

added. These micro-organisms are special because they don’t need oxygen to survive.They work without oxygen(air). They also need an environment that has the correct temperature and acidity. When conditions are correct the special micro-organisms perform a series of reactions called anaerobic digestion.Within this environment methane and other gases are produced. The methane gas is separated and used as biogas.

Hartman, Eviana (6 January 2008). "A Promising Oil Alternative: Algae Energy". The Washington Post. Retrieved 1 May 2014.

http://en.wikipedia.org/wiki/Algae_fuel