Biodiesel Production from Four Residential Waste Frying Oils: Proposing Blends for Improving the Physicochemical Properties of Methyl Biodiesel

The physicochemical properties of biodiesel fuels and their blends prepared from four residential waste vegetable frying oils (sunflower (FSME), canola (FCME), mixture of sunflower and rapeseed (FSRME) and corn (FSCME)) were evaluated and measured to determine the best blend. The results indicate that the stability of 10 biodiesel blends was above 10 h for 0-month, meeting the stability requirement regulated in EN 14214:2014 by adding FSCME, which depends on the concentration amount of FSCME. Besides, the results showed that all fuel samples did not meet the requirements of diesel fuel standards. Therefore, automobile gasoline is used as an additive to unmixed biodiesel in various concentrations to reduce the kinematic viscosity, density and cold flow properties. The results indicate that BG85 and BG80 have met the mixed pure biodiesel with gasoline fulfilled diesel fuel quality standard. Therefore, the samples with stability above 10 h were mixed with gasoline in 15% and 20% to reduce the cold flow properties and meet the specifications of the diesel fuel standards. Moreover, the effect of long-term storage on the properties of all samples was investigated under different storage conditions. The results indicate that higher storage temperatures and longer storage periods negatively influenced the properties of the fuel samples.