Fish oil mixed to castor oil for biodiesel production: antioxidant effects and renewable energy generation

Fish oil has been shown to be a viable alternative for the diversification of the energy matrix, since its use contributes to meet the need for new raw materials for the biofuel production. Castor oil has aroused interest in recent years and has come to be seen as a productive means for obtaining renewable fuel, standing out for presenting some anomalous properties in relation to other oils. The present study aimed to produce samples of biodiesel from a blend of castor oil/fish oil through the process of transesterification via basic catalysis, methyl route. Subsequently, physical-chemical analysis of the biofuel generated was carried out in order to ascertain its classification in the parameters required by the established standards and relate the results obtained through statistical tests. By the method used, except the iodine index, all physical-chemical analysis was within the required quality parameters. The kinematic viscosity complied with the limit acceptable in Brazil ranging from 4.16 to 5.87. Regarding the acidity index, the results of the samples showed an average of 0.29 mg KOH/g and all 11 samples met the acceptable limits. The results of the saponification index, in turn, were very satisfactory since the sample with the highest saponification index showed only 102.89 mg KOH/g. The iodine index results ranged from 125.33 to 141.51 g I2/100 g, demonstrating oxidative stability below expectations. Thus, as confirmed by the statistical analyses, the production of biofuel with a higher concentrations of castor oil must be tested in order to assess whether the addition of this oil can actually enable its action as an antioxidant additive.