Making Biodiesel from Algae

In this ever-expanding world, everything is being consumed at a very fast rate. Natural Resources are being depleted at a very fast rate and mankind is thinking of many ways to produce artificial energy. And one answer that has come up is Biodiesel. What is actually biodiesel? In a layman’s language Biodiesel refers to a non-petroleum-based diesel fuel consisting of long chain alkyl (methyl, propyl or ethyl) esters, made by transesterification of vegetable oil or animal fat (tallow), which can be used (alone, or blended with conventional petrodiesel) in unmodified diesel-engine vehicles.

Though there are many methods available and being researched upon but one of the common methods of producing it is by Algae. Making biodeisel with algae is quite a tedious process/ One must know what are actually Algae. Algae are some of the most robust organisms on earth, able to grow in a wide range of conditions without any problems. Algae are usually found in damp places or bodies of water and thus are common in terrestrial as well as aquatic environments.  Terrestrial algae are usually rather inconspicuous and far more common in moist, tropical regions than dry ones, because algae lack vascular tissues and other adaption’s to live on land. So cultivation of algae is an important part in this process.

Algae cultivation though a very easy process but cultivation of specific strains of algae for Biodiesel would however a bit more difficult, as they can require high maintenance and could get easily contaminated by undesirable species. And contamination would lead to improper production of biodiesel.

First algal oil has to be extracted from algae and then biodiesel has to produced from that Algal oil. There's no doubt, algae biodiesel is probably the most theoretical and experimental aspect of biodiesel. It is also very costly. There are mainly three methods of oil extraction from Algae –

•    Expeller/Press - When algae is dried it retains its oil content, which then can be "pressed" out with an oil press. Many commercial manufacturers of vegetable oil use a combination of mechanical pressing and Chemical Solvents in extracting oil.
•    Hexane solvent oil extraction - Algal oil can be extracted using chemicals. .Benzene and ether have been used, but a popular chemical for solvent extraction is hexane. The downside to using solvents for oil extraction are the inherent dangers involved in working with the chemicals. Benzene is classified as a carcinogen. Carcinogen is a chemical which harms humans.
•    Supercritical Fluid Extraction - This can extract almost 100% of the oils all by itself. This method however needs special equipment for containment and pressure. In this method , CO2 is liquefied under pressure and heated to the point that it has the properties of both a liquid and gas. This liquefied fluid then acts as the solvent in extracting the oil.

Now transesterification of  algal oil is  done.It is normally done with ethanol and sodium ethanolate serving as the catalyst.
Ethanol is reacted with the algal oil to produce biodiesel & glycerol. The end products of this reaction are hence biodiesel, sodium ethanolate and glycerol.

The end mixture is then separated using Ether and salt water, which is added to the mixture and mixed well. After sometime, the entire mixture would have separated into two layers, with the bottom layer containing a mixture of ether and biodiesel. Biodiesel is in turn separated from ether by a vaporizer under a high vacuum. As the ether vaporizes first, the biodiesel will remain.
Thus the process of making biodiesel from algae is now over and is ready for use.