Estudo do comportamento do equilíbrio líquido-líquido nas etapas de decantação e lavagem de biodieseis etílicos por meio da modelagem termodinâmica NRTL

Abstract

The objective of this work was to evaluate the ELL behavior for major components present in systems representative of the decantation and washing stages of ethyl biodiesel from crambe, forage, macaúba and palm oils. In this sense, parameters of the thermodynamic model NRTL were adjusted from the algorithm in Fortran “TML-LLE2 for mass fractions” for systems consisting of glycerol + ethanol + biodiesel and by water + ethanol + biodiesel, all at 298.15 K; the ternary diagrams of the systems; Sensitivity analyzes were performed from the parameters adjusted to the model, altering the compositions of the mixing points in ethanol and water, respectively, for systems with glycerol and water. The NRTL model satisfactorily represented the behavior of ELL systems with overall mean deviations of less than 0.7% and 1.3% for systems containing glycerol and water. In glycerol-containing systems, higher affinity of ethanol was observed for glycerol than for biodieses while a larger phase separation region was observed for water-containing systems. The increase in the water content at the point of mixing led to a decrease in ethanol mass fractions in the biodiesel rich phase, a decrease in the biodiesel content in the water rich phase and a gradual decrease in the water content in the biodiesel rich phase. From the study, it can be affirmed that the partial ethanol removal in the decantation stage reduced the losses of biodiesel to the glycerol rich phase, the contamination of the rich phase in biodiesel with glycerol and water, leading to the reduction of the generated effluents in the washing process.