Evaluation of the behavior of the kinetic parameters of the oxidation reaction of biodiesel in contact with metal alloys during storage

Resumo

Biodiesel has low oxidative stability due to the high content of unsaturated esters in its composition, and its degradation can occur due to exposure to air, humidity, light, heat, contaminants by microorganisms and in the presence of metals. This study aims to evaluate the influence of alloys of carbon steel, steel 1020 and sample of industrial pipe in biodiesel storage. The sample of biodiesel in contact with the pipe sample presented lower values of the induction period and, consequently, higher rate constants, accelerating biodiesel degradation. The biodiesel in contact with carbon steel and steel 1020 showed a lower degradation when compared to the industrial pipe sample. The biodiesel in the presence of the carbon steel alloy presented higher oxidative stability that of the sample in the presence of steel 1020. Some samples presented more complex oxidation reactions with deviations of the linearity described by Arrhenius.