Algae for your fuel tank—New process for producing biodiesel from microalgae oil
http://www.eurekalert.org/pub_releases/2012-01/tum-afy011012.php[font face=Times, Serif]Public release date: 10-Jan-2012
Contact: Dr. Andreas Battenberg
battenberg@zv.tum.de
49-892-891-0510
Technische Universitaet Muenchen
[font size=5]Algae for your fuel tank[/font]
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New process for producing biodiesel from microalgae oil[/font]
[font size=3]The available amount of fossil fuels is limited and their combustion in vehicle motors increases atmospheric carbon dioxide levels. The generation of fuels from biomass as an alternative is on the rise. In the journal Angewandte Chemie, Johannes A. Lercher and his team at the Technische Universitaet Muenchen have now introduced a new catalytic process that allows the effective conversion of biopetroleum from microalgae into diesel fuels.
Previously known methods for refining oil from microalgae suffer from various disadvantages. The resulting fuel either has too high an oxygen content and poor flow at low temperatures, or a sulfur-containing catalyst may contaminate the product. However, other catalysts are still not efficient enough. The Munich scientists now propose a new process, for which they have developed a novel catalyst: nickel on a porous support made of zeolite HBeta. They have used this to achieve the conversion of raw, untreated algae oil under mild conditions (260 °C, 40 bar hydrogen pressure). Says Lercher: "The products are diesel-range saturated hydrocarbons that are suitable for use as high-grade fuels for vehicles."
The oil produced by the microalgae is mainly composed of neutral lipids, such as mono-, di-, and triglycerides with unsaturated C18 fatty acids as the primary component (88 %). After an eight-hour reaction, the researchers obtain 78 % liquid alkanes with octadecane (C18) as the primary component. The main gas-phase side products are propane and methane.
Analysis of the reaction mechanism shows that this is a cascade reaction. First the double bonds of the unsaturated fatty acid chains of the triglycerides are saturated by hydrogen. Then, the now saturated fatty acids take up hydrogen and are split from their glycerin component, which reacts to form propane. In the final step, the acid groups in the fatty acids are reduced stepwise to the corresponding alkane.
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http://onlinelibrary.wiley.com/doi/10.1002/anie.201106243/abstract