It is known that biodiesel density mainly depends on its methyl esters content and the re­mained quantity of methanol (up to 0.2% m/m according to JUS EN 14214 [JUS EN 14214:2004]); hence this property is influenced primarly by the choice of vegetable oil [Mit- telbach, 1996], and in some extent by the applied purification steps. the mean density value of produced biodiesel was 0.90 g/cm3, while this value was more than Egyptian diesel (0.82-0.87g/cm3). but met the density value specified by JUS EN 14214 [JUS EN 14214:2004] to be in the range 0.860-0.900 g/cm3 at 15 0C. This property is important mainly in airless combustion systems because it influences the efficiency of atomization of the fuel [Felizardo et al., 2006].

1.5.1. Kinematic viscosity at 40 0C

Even more than density, kinematic viscosity at 40 0C is an important property regarding fuel atomization and distribution. With regard to the kinematic viscosities that were in the range from 32.20 to 48.47 mm2/s, the feedstocks differed among themselves significantly. The vis­cosities of MEs were much lower than their respective oils (about 10 times) and they met the required values that must be between 3.5 and 5.0 mm2/s [JUS EN 14214:2004]. Comparing our MEs, the increase of the viscosities was observed more than Egyptian diesel, EN14214 and D-6751 (14.3, 7, 5 and 6 respectively) as shown in Table (3). However, the kinematic vis­cosity at 100 0C of MEs produced from frying oil was met the viscosity range of Egyptian diesel, EN14214 and D-6751 (4.3, 7, 5 and 6 respectively). Predojevic (2008).