Biodiesel fuels composition, typical

The pyrolysis products of vegetable oils and wood are highly dependent on the chemical composition of the raw material, and the elemental composition of biofuels typically resembles that of biomass. One possibility is to apply fast pyrolysis to these raw materials directly or after their alkaline hydrolysis for manufacturing liquid fuels (mainly biodiesel).An interesting approach is also the direct pyrolysis of the CTO soap for producing biofuel. In this process concept, sodium could also be recovered simultaneously in the form of Na2C03, thus eliminating, for example, the... 

Most current studies of biodiesel chemistry, and the detailed chemical kinetic mechanisms derived therefrom, are based on surrogate molecules and mixtures the proxies contain the same or similar chemical functionalities as actual fuels, but are simplified systems designed to isolate particular aspects of the chemistry or behavior. Biodiesels in current use are alkyl esters of saturated and unsaturated fatty acids, with hpid chain lengths that range from about C14 to C22 (most typically C16 to C18), with the chemical composition varying from oil to oil. The surrogates used in the models are often smaller saturated and unsaturated lipids such as MB (and methyl butenoate), methyl hexanoate, or MD (and methyl decenoate). 

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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