(421j) Conversion of Triacylglycerides to Free Fatty Acids: Application to Algal Systems

The third generation of biofuels, algae, is of growing interest in the pursuit to find alternative fuel sources.  The appeal of algae stems from its high yield of carbon rich components per unit area, use of carbon dioxide for growth,  and minimal interruption of food production.  Biodiesel, derived from triacylglycerides (TAGs), is commonly produced by the transmethylation reaction.  This reaction produces fuel as fatty acid methyl esters (FAMEs) by reacting fatty acids from lipids, found in plant oil or animals fats, with methanol in the presence of an acid or base catalyst.  Algal feedstocks are harvested from aquatic environments and contain high concentration of water which competes with methanol in conversion of lipids to FAMEs.  This high water content inspired the development of a two step procedure to produce free fatty acids from TAGs.  In the first step, subcritical water is reacted with lipids to free fatty acids by hydrolysis.  Syndiesel can then be formed from free fatty acids via hydrothermal liquefaction or to FAME without the use of a catalyst.   

Hydrolysis of soybean oil with high water content to free fatty acids provides a model system for optimizing reactor conditions for algal lipid hydrolysis.  Various operating and processing parameters were explored and kinetics have been modeled.   The reaction parameters explored for the hydrolysis of soybean oil are compared and contrasted with results obtained from algal lipid hydrolysis results.