Pour Point and Predictive Models for the Viscosity-Temperature Non-Linear Behaviour of Ternary Fuel Blends for a Compression Ignition Engine

Due to the ever-increasing consumption of fossil fuels, their impact on the environment, and the volatility of the market, it is advisable to use biofuels that can be produced locally from renewable sources, which supports the local economy, agriculture, and related processing industries. This article deals with how to improve the flow properties and pour point of biofuels for diesel engines. For the experiment, biodiesels in the form of rapeseed methyl ester (RME) and methyl ester made from waste animal fats and tallow (WAFME) were used. The pour point, viscosity, and density of WAFME were improved by mixing with RME and/or by adding bio-alcohols (alcohols produced from biomass, e.g., lignocellulosic). All used biofuels were classified as 2nd generation biofuels. The flow properties of the mixtures were monitored and subsequently modelled at temperatures from -10 to 60 °C. The addition of bio-alcohol had a statistically significant effect on the decrease in the viscosity and pour point of ternary blends (p < 0.05). Mathematical models of the dependence of kinematic viscosity on the temperature of mixtures (power law, exponential, Arrhenius, and Vogel) were created.