HEGEL Pablo Ezequiel
congresos y reuniones científicas
Supercritical alcoholysis of sunflower wet sludge to produce fatty esters
G. SOTO; A. VELEZ; P. HEGEL; G. MABE; S. PEREDA
Congreso; 13th European Meeting on Supercritical Fluids; 2011
In the last decade the production of soybean and sunflower oil has greatly increased worldwide. Together with it, the market of the oil refining by-products (phospholipids sludge and distillates of the deodorizer) is rapidly changing. Even though these residues contain high-added value products, their cost are decreasing, becoming sometimes a waste with disposal associated problems. Particularly, soy oil has a high concentration of phospholipids, thus an important volume of sludge (also called gums) is being produced. Sunflower oil gums contains approximately ∼45% water, ∼25% oil and ∼30% phospholipids. These are mainly used as ingredient for animal food, but soy gums are of low quality due to its low nutritive value (high water content) compare to gums derived from other vegetable oils. Moreover, gum processing to recover oil or phospholipids is complicated because of its high viscosity and poor fluid properties. Thus, the processes in general require high amount of solvent becoming expensive and contaminant. In this work we propose to perform the direct alcoholysis of phospholipids and oil enclosed in the wet gum using supercritical ethanol. Nowadays biodiesel commercial production is carried out with basic catalysts which cannot be use in the presence of phospholipids. Therefore, the process that we propose here can be used as a side-counterpart in biodiesel plants to increase the oil yield towards biodiesel. Tested conditions are based on a statistical design of experiments to determine the effect of the operating parameters such as temperature (280-320 °C), alcohol mass fraction (0.5 to 0.8 m/m of ethanol) and reaction time (20 to 50 min.) in the process. In all the studies a complete conversion of lipids was observed. Hexane insoluble solid substrate was obtained (below 30%) in the reaction product. After removal of volatile compounds, reactants and reaction by-products, the oily phase has a fatty ester composition higher than 50 % by mass fraction.