LAUSR

The sediments that form during biodiesel oxidation decrease the ignition quality, damaging the injector nozzle, the filter and the motor operation system. They may form in a very fast way, and their correct quantification is still a problem. The insoluble oxidation products due mainly to biodiesel degradation in diesel/biodiesel blends may be characterized by several analytical techniques. The conventional methods currently used for sediment quantification are gravimetric, but do not present repetitive results, still presenting a technical challenge to be solved. In this work, the thermal degradation process of a commercial soybean ethylic biodiesel (BS100) was evaluated by thermogravimetry, derivative thermogravimetry and by infrared spectroscopy, after being submitted to different aging procedures. Analyses of samples aged at 43 °C, 110 °C and 150 °C were compared to the original non-aged sample. As diesel engines operate under oxidizing conditions, thermal analyses were performed with synthetic air and the results were compared with the analyses in nitrogen.