Análise da estabilidade térmica dos biodieseis de algodão, mamona e babaçu via rancimat e dsc

Abstract

Several factors led to the search for alternative sources of energy to fossil fuels. Among these are the environmental concern and the need to diversify the energy matrix. In this context, Brazil is one of the greatest producers with low utilization of its great potential of production. In this context, this country has one of the greatest territorial extension and a climatic diversity that allows a production of several oilseeds throughout the year, and simultaneously, an underutilized production infrastructure. However, there is a need for strict control for biofuels (e.g. biodiesel) to guarantee good performance, engine integrity and safety in transport and handling. Oxidation affects biodiesel’s quality, then, it is essential keeping control on the possible degradation during the storage process. This study aims main to evaluate the thermal and oxidative stability of biodiesel, obtained through the methylical route, derived from three different oilseeds with great production potential in the Brazilian northeast - cotton, castor and babassu. The biodiesel samples were analyzed by Differential Scanning Calorimetry (DSC) before and after the accelerated oxidation test via Rancimat. The results showed, despite the great difference of the methods used, the DSC analysis is able to realize the difference in thermal behavior between the samples before and after the accelerated oxidation test. According to the results, both studies showed, through the Induction Period and Activation Energy, that cotton biodiesel (PI: 3,48 h – Ea: 137,05 kJ/mol) appears to be more prone to oxidation, followed by babassu biodiesel (PI: 5,43 h – Ea: 182,52 kJ/mol), and finally castor biodiesel (PI: 14,74 h – Ea: 258,78 kJ/mol).