Biodiesel fuels properties, typical

Biodiesel is diesel fuel produced from vegetable oils and other renewable resources. Many different types of oils can he used, including animal fats, used cooking oils, and soybean oil. Biodiesel is miscible with petroleum diesels and can he used in biodiesel-diesel blends. Most often blends are 20 percent biodiesel and 80 percent traditional diesel. Soy diesel can be used neat (100%), hut many other types of biodiesel are too viscous, especially in winter, and must be used in blends to remain fluid. The properties of the fuel will vaiy depending on the raw material used. Typical values for biodiesel are shown in Table 1. 

Biodiesel methyl esters blend quite easily into petroleum based conventional diesel fuel. Biodiesel esters typically have better lubricity properties and higher cetane number ratings than conventional diesel fuel, but have poorer water demulsibility and color stability properties. At sub-zero temperatures, the handling characteristics of biodiesel becomes more difficult to control than conventional diesel fuel. 

Table I-E-4 shows physical and chemical properties for No. 1 diesel fuel. No. 2 diesel fuel, and a typical biodiesel made from soy oil (Canakci, 2005). The fatty acid composition (%) for the soybean oil used was C16 0, 10.5 C17 0, 0.11 C18 0, 4.76 C18 l, 22.52 C18 2, 52.34 C18 3, 8.19, C20 0, 0.36 unknown components, 0.48 % saturation, 16.3. The composition of the biodiesel methyl esters prepared from the soybean oil is similar C16 0, 10.56 C17 0, 0.11, C18 0, 4.74 C18 l, 22.51 C18 2, 52.39 C18 3, 8.22 C20 0, 0.44 unknown components, 0.44 % saturation, 16.3. As seen from table I-E-4, the biodiesel has similar properties to fossil diesel. Biodiesel has a greater viscosity and tendency to gel than conventional diesel fuel, which restricts its use at low ambient temperature unless sufficient heating of the fuel and engine components is provided.

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