The concept of using microalgae as an alternative source of energy by converting it into biofuel through the application of pressure and heat has been the subject of research for several decades now. Conventionally, both mechanical and chemical methods have been used to extract the oil from the algae and convert it from its crude form into something more viable. Mechanical methods usually include presses, which squeeze the oil out of the algae through the application of pressure. Another mechanical method involves the use of ultrasonic waves to break the cell walls of the microalgae and in turn release the oil. Chemical methods include using specific organic chemical solvents that dissolve the oil in the algae and extract it in this manner. Once the crude form of the oil is extracted, it is made to undergo a process called transesterification, which results in the formation of biodiesel, ready to be used.
The methods described above have been tested extensively using different strains of algae and different physical and chemical conditions. The results are quite promising. The head of the Algal Biomass Organization has stated that algae biofuel could become commercially viable by 2018. However, until recently there have been no obvious signs of this happening. Last week, researchers at Savage Labs, University of Michigan, announced that they have come up with a quick and efficient method to convert microalgae into biofuel that they claim takes as little as a minute to complete. This method results in an impressive 65 percent conversion of algae into crude oil. Savage Labs’ choice of microalga is the strain of genus Nannochloropsis. Their method is said to mimic the natural process of conversion of marine organisms into biofuel. It involved filling a steel pipe connector with 1.5 millilitres of algae solution, covering the ends and inserting it into sand at a temperature of almost 600 degrees Celsius. Since only a small volume was used, this ensured that the algal solution was completely heated through. However, since the solution was heated for just a minute, it reached a temperature of about 290 degrees before it was pulled out. Previous results conducted by the team showed that optimum results were obtained after treating the algae for 10 to 40 minutes at a temperature of 300 degrees.
While the discovery of this one-minute cooking process for the formation of biofuel is a reason to rejoice, the team is still unaware as to why this method works better than other, longer procedures. However, they do have some guesses. They believe that the reactions involved in the formation of biocrude take place at a much faster rate than previously thought. The fast heating, it is suggested, might prevent unwanted reactions such as decomposition of the biocrude from taking place. The advantage of shorter reaction times is that smaller reactor sizes are possible, thus reducing the cost of building a fully functioning power plant. Unlike other algae oil extraction methods, this one harvests not only the energy contained in the oil, but also breaks down and collects energy from proteins and carbohydrates present in the solution. This results in a whopping 90 percent energy retention.
Savage Labs is also working on better methods of refining the biocrude to make it commercially viable. Earlier this year, they came up with a purification method that resulted in a biocrude consisting of 97 percent carbon and hydrogen, a number not achieved by anyone else. When microalgae biofuel becomes economical, an area about the size of New Mexico would be sufficient to harvest algae and provide enough biofuel to meet current consumption rates in the United States. Unlike other biofuel sources (such as corn), algae would not take up prime farmland and could thrive on any water body.
It is hoped that we wean ourselves off our current dependence on fossil fuels and are able to switch to a greener (literally!), more sustainable fuel source within the next decade, and thereby ensure we leave our planet in still habitable conditions for our children.
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