Abstract
Pure vegetable oils can be used as alternative fuel for standard unmodified diesel engines, provided the oil viscosity has been lowered by heating before they enter the fuel injection system. In its role as diesel fuel, a vegetable oil has to have, among other parameters, a low acidity and low contents of phosphorus and the alkali earth metals Ca + Mg. Such parameters can be achieved by appropriate partial refining of oil by degumming. In this article, three common ethanolamines, monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA), were used as degumming agents for removing non‐hydratable phospholipids from crude rapeseed and sunflower oils. Among the studied ethanolamines, MEA is the most effective for the removal of phosphorus. After degumming with MEA (0.5 wt‐%), the phosphorus content in rapeseed oil was reduced from 445 to 3.5 ppm, and from 163 to 2.2 ppm in sunflower oil. After oil treatment with MEA (1.0 wt‐%), the residual content of Ca and Mg decreased from 136 to 4.2 ppm and from 55.4 to 1.1 ppm in rapeseed oil. In sunflower oil, the values of Ca and Mg decreased from 23.9 to 1.5 ppm and from 24.6 to 1.0 ppm. The acid value of the oils also decreased after degumming with ethanolamines. The advantage of this oil treatment process is that it takes place at ambient temperature, resulting in lower production costs and simpler technology.