Biodiesel is a renewable fuel derived from a biomass. "Bio" represents its renewable and biological source in contrast to petrodiesel fuels; "diesel" refers to the use in diesel cycle engines. Biodiesel is an alternative energy source for Brazil that brings several advantages compared to petrodiesel. However, biodiesel it is considerably less stable, more susceptible to oxidation reactions and more corrosive than diesel, unless it is modified or treated with additives (synthetic antioxidants). Corrosion caused by biodiesel is a relevant problem associated to the incompatibility of biodiesel with different metallic and polymeric materials, which is extremely important for durability of automotive engines. The biodiesel corrosiveness is directly connected to the chemical composition of the feedstock (raw materials) and other factors that leads to the biodiesel oxidation and degradation as impurities, temperature and oxygen. Thus, the main aim of this project is investigated the influence of feedstock (soybean and palm) into the biodiesel corrosiveness in relation to the metals present in the fuel circuit of internal combustion engines, correlating with the degradation which also reflects in the problems of filters clogging and engines wear. The study will be made by the association of physico-chemical characterization, electrochemical and gravimetric techniques. Representative aspects of the storage and use conditions, such as the temperature effect and oxygen content will also be evaluated on the biodiesel corrosiveness and degradation in order to find ways to minimize metal's corrosion. The characterization of biodiesel quality and degradation will be performance according to the specifications established by the ANP combined with Raman spectroscopy, infrared spectroscopy, determination of hydroperoxides (ASTM D3703) and electrochemical impedance spectroscopy using a classic conductivity cell as electrochemical sensor. The biodiesel corrosiveness from soybean and palm on the copper, brass and carbon steel will be evaluated by weight loss measurements performed in a cell (apparatus) based on the model proposed by ASTM G31 standard and electrochemical impedance spectroscopy using microelectrodes. The corrosion products will be analyzed by X-ray diffraction and SEM.
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