The influence of animal fat type and purification conditions on biodiesel quality

Production of biodiesel from waste animal fats has a great potential since this feedstock does not compete with the food industry and leads to the global reduction of wastes. The type of feedstock as well as the presence of impurities highly influences the quality of biodiesel. Too high concentrations of glycerol and glycerides in biodiesel negatively influence the fuel quality and can generally reduce the engine durability, so crude biodiesel needs to be purified. One alternative method of purifying biodiesel is extraction with deep eutectic solvents. Biodiesels were synthesised from five types of waste animal fats: veal and beef tallow, lard, chicken and goose fat, by means of chemical transesterification catalysed by alkali catalyst. Due to the fact that the presence of impurities negatively influences the quality of biodiesel, crude biodiesels were purified. Liquid-liquid extraction with previously prepared deep eutectic solvent choline-chloride/ethylene-glycol (molar ratio 1:2.5) was selected as the purification method. Experiments were performed at different mass ratio solvent/biodiesel in a laboratory scale batch extractor equipped with mechanical stirrer and optimal mass ratio was defined. Biodiesels were characterised and their properties were conipared with the standard specification. Free glycerol from animal fats biodiesels was efficiently removed by the selected solvent. (C) 2017 Elsevier Ltd. All rights reserved.