Produção de biodiesel e obtenção de dados de equilíbrio líquido-líquido a partir do óleo de crambe (Crambe abyssinica Hochst)

Abstract

The biodiesel production occurs through the transesterification reaction, which corresponds to the mixture of excess oil and alcohol in the presence of a catalyst. However, both in the reaction and in the separation step there is the presence of immoble phases. In the reaction stage the oil and alcohol are partially miscible and the product formed from the reaction is also partially miscible, consisting of a heavy phase rich in glycerol and a light phase rich in ester. In this way, the knowledge of the net-liquid equilibrium of systems related to these steps becomes extremely important for optimization of these units. Thus, this work has the objective of studying the liquid-liquid balance of systems involving: crambe oil + ethanol + crambe biodiesel; Soybean oil + ethanol + soybean biodiesel; Canola oil + ethanol + canola biodiesel; Corn oil + ethanol + corn biodiesel at temperatures of 30 ° C and 50 ° C. The methodology used to obtain the bimodal curves was the fog point, which consists of the titration of a mixture under agitation until turbidity, with constant temperature. The validation of the methodology was performed comparing the data obtained in this work to the soybean oil + ethanol + soybean biodiesel system at 30 ° C with those in the literature. It is observed that the heterogeneous region for all the systems is higher in the temperature of 30 ° C compared to the temperature of 50 ° C, that is, with the increase of the temperature there was an increase of the homogeneous region, favoring the reaction. It can also be verified that as the biodiesel is formed by the transesterification reaction, as it is soluble in both the oil and the alcohol, the mixture tends to the homogeneous region. The experimental data presented in this work contribute with liquid-liquid equilibrium information from the reaction stage of the biodiesel production process.