Irina Nita

Estimation of the refractive index of diesel fuel+biodiesel blends

Abstract For now, biodiesel is the commonly accepted biofuel as a substitute for diesel fuel in internal combustion engines. Diesel fuel blends with up to 20% biodiesel can be used in diesel engines without any modification. A lot of studies regarding diesel fuel+biodiesel blends properties are presented in the literature. Some of the important properties of diesel fuel+biodiesel blends can be evaluated from other blends properties. For example, density and viscosity of biodiesel blends can be predicted based on blend refractive index. More than that, refractive index can be used as a reliable physical property to predict transesterification reaction progress. As a result, the refractive index of diesel fuel+biodiesel blends is important in order to characterize these blends or to monitor the evolution of transesterification process of vegetable oils or animal fats. The refractive index of diesel fuel+biodiesel blends can be experimentally determined or evaluated based on refractive indices of diesel fuel and biodiesel. The aim of this study was to estimate the accuracy of refractive index of diesel fuel +biodiesel blends calculation, using models initially proposed to evaluate the refractive index of a binary liquid mixture. It was shown that the refractive index of diesel fuel+biodiesel blends can be accurately predicted from refractive indices of the components of the blend. Wiener, Heller and Edward equations can be recommended to predict with a great accuracy the refractive index of diesel fuel+biodiesel blends.

Study of the refractive index of gasoline+alcohol pseudo-binary mixtures

Abstract The properties of gasoline change as a result of blending with a bioalcohol, affecting the behavior of the pseudo-binary system. The aim of this paper is to present experimental data of the refractive index for pseudobinary mixtures of a reformate gasoline with ethanol, isopropanol and n-butanol over the entire composition range and for temperature ranging from 293.15 K to 313.15 K. The accuracy of different equations to predict the refractive index of the mixtures was tested. The best prediction accuracy (the lower AAD) corresponded to Eykman and Lorentz-Lorenz mixing rules. A logarithmic equation proposed to correlate the refractive index with composition and temperature of gasoline+alcohol mixtures showed a good accuracy (the absolute average deviation AAD < 0.052%). The deviations in refractive index for investigated systems are negative over the entire composition range and at all investigated temperatures.

Study of density and viscosity for ternary mixtures biodiesel+diesel fuel + bioalcohols

Abstract The increase of the environment pollution, together with the instable price of crude oil led in the last years to a renewed focus on biofuels. As the demand in the transport sector is continuously increasing, and taking into account the benefits of biofuels, it is expected that the market demand for biofuels to be increased in the near future. In this context, it will be interesting to investigate if new types of biofuels could be used as mixtures with other fuels for internal combustion engines. The aim of this paper is the study of density and viscosity variation with composition and temperature for ternary mixtures biodiesel + diesel fuel + bioalcohol. Experimental densities and viscosities data for ternary blends diesel fuel+biodiesel +isopropyl alcohol/1-butyl alcohol are presented, and some empirical models proposed to predict these properties for binary systems diesel fuel+biodiesel are evaluated for the proposed ternary blends.