Abstract
Investigating the suitability of turbidimetry as an alternative method to determine the precipitate content and fuel filter plugging potential of biodiesel was the primary objective of this study. First, different levels of precipitate isolated from turbid palm oil biodiesel (POB) were added to distilled POB, and turbidity of the resulting blends at 25 °C was measured. Turbidity had high repeatability (average standard deviation < 0.07 FNU), evidencing the suitability of turbidimetry. In addition, a simple first-order model capable of explaining more than 99 % of the turbidity variability with the level of precipitate was obtained by lineal regression analysis. Blends of turbid and non-turbid POB were then prepared, and turbidity of the resulting blends at 25°C were measured. The blends were also analyzed in accordance with the ASTM D7501 and D7321 Standard Test Methods. Thus, a simple first-order model capable of explaining more than 98 % of the turbidity variability with the precipitate content was obtained by lineal regression analysis. More important, it was found that turbid POB possessing turbidity lower than 5.3 FNU would meet the ASTM D6751 limit for CSFT. Finally, the effect of temperature effect on turbidity was also examined at 25, 35, and 45 °C, but it was not statistically significant.
