Influência das propriedades fluidodinâmicas na matriz do biodiesel metílico e suas misturas diesel/biodiesel de óleo de peixe

Abstract

The efficiency of an engine during the combustion process depends, among other factors, on the viscosity of the fuel. A high viscosity decreases the fuel volatilization resulting in an incomplete combustion. The biodiesel added to diesel fuel leads to improvements in their characteristics with respect to combustion gases emissions to the atmosphere. Sudden drops in temperature are responsible for increasing the viscosity and crystallization of fatty esters of biodiesel components causing damage in the engine. This concerns to both, biodiesel and mineral diesel, because the late is composed by saturated hydrocarbons which tend to form crystals at low temperature. To minimize this limitation biodiesel from fish oil blended with diesel, can improve the fluid dynamic properties of the fuel in different conditions of evaluation. GC-MS analysis revealed the presence of 31.57% of methyl linoleate as the major component of biodiesel from fish. The infrared spectra indicated the efficacy of transesterification reaction to obtain the methyl ester. From the viscosity curves as a function of temperature, was observed that the binary mixtures shown a similar profile to that of diesel, a sharp reduction in viscosity with increasing temperature in the range 5-15 ° C, this event is evidenced in the TMDSC cooling curves in the melting process followed by the formation of crystals, melting temperature and freezing, which were correlated with flow techniques. The gradual addition of biodiesel do not cause significant changes in the fluidity and fog points. To pure biodiesel was observed a sharp decrease of temperature, explained by the presence of (Z)-unsaturated esters in its composition, which obstruct the packing between molecules. Increasing the concentration of biodiesel in the diesel matrix gives a slight increase in consumption and viscosity of the fuel remaining so within the limits allowed. In conclusion fish oil biodiesel/diesel blends are a excellent alternative for using in diesel cycle engines.