We will discuss an innovative process for the direct conversion of algal biomass to biofuels under supercritical ethanol conditions. The direct liquefaction and conversion of wet algal biomass containing about 80% of water to biodiesel under supercritical ethanol conditions has been demonstrated in our laboratory. This one-step process allows for simultaneous extraction and transesterification of wet algal biomass to fatty acid ethyl esters. The process conditions are milder than those required for pyrolysis and prevent the formation of bi-products. In the proposed process, fatty acid ethyl esters can be produced from polar phospholipids, free fatty acids, and triglycerides. The process parameters studied in this work are algae to ethanol (wt/vol) ratio (1:3 � 1:15), reaction temperature (245 �C-270 �C), and reaction time (2 min. � 25 min.). About 67% (of total lipids) conversion was achieved at 265 �C and 10 minutes of reaction time. The fatty acid ethyl esters were analyzed using GC-MS and FTIR after purification. TGA analysis of algal biomass and the final biodiesel products will be presented along with the TEM images of the biomass sample before and after the supercritical ethanol transesterification. The single-step process has the potential to provide an energy efficient and economical route for algal biodiesel production.

Direct conversion of algae to biodiesel under supercritical ethanol conditions

243rd National Meeting (2012)

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