Study of the biodiesel corrosivity against metallic materials

Abstract:
Biodiesel production in Brazil, is expected to increase significantly over the coming years as there is government plan to increase the percentage of biodiesel in diesel. With the new Brazilian energy matrix, it becomes increasingly necessary to know the behavior of metallic materials used in transport and storage systems of new fuels, in particular, of biodiesel. The corrosivity of traditional fuels against the structural metallic materials is well known both in the pipeline and storage tank systems, which still does not occur with biodiesel. In this study, the corrosivity of biodiesel obtained from bovine fat, soybean and castor oil against carbon steel SAE 1020 and austenitic stainless steel AISI 316 was evaluated, through gravimetric corrosion tests at different temperatures, at three different moisture levels and in closed and open environments. Stainless steel was also studied after sensitization heat treatment to simulate possible changes in microstructure due to welding operations. As the number of variables involved in the study was very large, a statistical design of experiments was adopted which reduced by 50% the amount of tests. This paper describes the adopted test methodologies, the obtained results and the discussion of the influence of the tested variables on the corrosion processes. The corrosivity of the three types of biodiesel was also verified after aging for 60 days and 120 days. The results showed no significant change in the corrosivity of either biodiesel as a function of aging time. Testing was also performed according to the NACE TM 0172 standard test method which indicates a corrosion inhibition effect of biodiesel from castor beans.


Reference:
ALMEIDA, Neusvaldo Lira de; PANOSSIAN, Zehbour ; BONFIM, André Luiz Castro; PIMENTA, Gutemberg de Souza; TAQUEDA, Maria Elena; FERREIRA, Raphael. Study of the biodiesel corrosivity against metallic materials. In: RIO PIPELINE CONFERENCE & EXPOSITION, 2011, Rio de Janeiro. Proceedings… 11 p.