Accurate knowledge of the components in the purification of biodiesel is important in achieving consistency in quality for the separation and purification process. In this paper, ternary phase diagrams were
used to study the phase separation and purification of tropical almond biodiesel at temperatures of 20 C,
30 C and 40 C. The biodiesel was produced using alkaline transesterification of the seed oil. The biodiesel was characterized using ASTM and EN standard methods. A modified cloud point titration procedure under constant temperature was used to determine the tie lines and binodal compositions. The
phase mixture compositions were determined using gas chromatographic method. Distribution coefficient and selectivity analysis were performed and data accuracy, consistency and reliability were done
using a first-order linear polynomial model. The result revealed free fatty acid values for the oil and the
biodiesel as 0.63 and 0.23 respectively. The data quality and reliability showed a high coefficient of
determination of 0.9998, adjusted coefficient of determination of 0.9887, a standard deviation of 0.0327,
and a correlation coefficient of 0.8349 at the investigated temperatures. Methanol was prevalent in the
glycerol phase. Ternary phase diagrams provided the visual means of estimating the distribution of the
components.