Biodiesel fuels cetane number

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. 

Van Gerpen, J. H. 1996. Cetane Number Testing of Biodiesel. In Cundiff, J. S., Gavett, E. E., Hansen, C., Peterson, C., Sanderson, M. A., Shapouri, H., and Van Dyne, D. L. (Eds.), Proc., Third Liquid Fuel Conference Liquid Fuel and Industrial Products from Renewable Resources (pp. 197-206). St. Joseph MI American Society of Agricultural Engineers. 

Standard canola oil is high in CIS fatty acids, about 95%, which is higher than the other commodity vegetable oils. It is high in CIS In - 9 oleic acid at about 60%, much higher than any other vegetable oils, and it is relatively low in polyunsaturated fatty acids, linoleic at about 21%, and linolenic at about 10%. Viscosity, cold hlter plugging point, and cetane number are some of the most important biodiesel fuel properties influenced by fatty acid composition. 

Furthermore, biodiesel is variable depending on the source of the fuel and its age (27). For example, Monyem and Van Gerpen (27) observed decreased carbon monoxide and hydrocarbon emissions from oxidized neat biodiesel when compared with unoxidized biodiesel. In addition, cetane number is inversely proportional to iodine value (28) and proportional to biodiesel age (29). 

The Calculated Cetane Index (CCI), though not an accurate predictor of Cetane Number for biodiesel, since it is based on a calculation using specific gravity and the distillation curve, was used to estimate the Cetane Number of the biodiesel and two diesel fuels. From the results it can be seen that biodiesel has a CCI value higher (55) than that of diesel No.2 (49). This accords the biodiesel with better cold-start properties, minimizes the formation of white smoke (emissions), and leads to less engine noise and hence improved engine durability and reduced fuel consumption. ... 

Biodiesel. Biodiesel appears as one of the attractive renewable energy sources. It refers to all biofuels of similar cetane number as that of diesel. Most commonly used biodiesel consists of fatty acid methyl esters (FAME), with physical characteristics close to fossil fuel. FAMEs are usually prepared by... 

Tables 6 contains, respectively, the properties of FAMES collected from the literature and the results of the prediction of quality parameters of oleaginous yeast and microalgae (Lacerda et al. 2013) compared with the American, European, and Brazilian standards. The values of heat of combustion (HC), index of oxidative stability (OSI) and iodine value (II) are out of limits imposed by these standards, however, the values of density (p), viscosity (u) and cetane number (CN) are within it. Even though the indexes are slightly out of bounds, the biodiesel obtained from Chlorella vulgaris and Lipomyces starkeyi may still be used as fuel.

Bamgboye, A.I., Hansen, A.C., 2008. Prediction of cetane number of biodiesel fuel from the fatty acid methyl ester (FAME) composition. International Agrophysics 22, 21—29. 

BTL diesel is a renewable fuel of excellent quality, compared to both fossil-derived diesel and first-generation biodiesel produced via the transesterification of vegetable oils. BTL synthetic fuel consists mainly of linear paraffinic hydrocarbons with almost zero aromatics and sulfur compounds. The physical properties of BTL diesel presented in Table 18.6 (Rantanen et al., 2005) demonstrate its very high cetane number that can reach up to 75, much higher than conventional diesel. The big advantage of BTL diesel is that it is directly usable today in the transportation sector and furthermore it may be suitable for future fuel cell vehicles via on-board reforming since it is free of sulfur. 

---