Iodine value , biodiesel oxidative

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 ASTM standard does not give restriction to the iodine value of methyl esters but the European biodiesel standard (EN 14214) states that the iodine value should be no more than 120. JCME is within the requirements of EN 14214. The iodine number of conventional (automotive) diesel fuel is reported to be 10. Based on the results shown in Table 2, the iodine value of the methyl esters differs only slightly from that of their parent oil. The iodine value derived from the GC-MS chromatograms are higher than those derived from the Wijs solution method, mainly because Equation 1 assumes full iodonization and treats all the double bonds as being equally reactive to oxidation. ... 

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.

Duarte and Maugeri (2014) studied lipid production by Candida sp. LEB-M3 cultivated in pure and raw glycerol. The feasibility of biodiesel production by the yeast Candida sp. LEB-M3 was indicated by predicting FAME properties for pure and raw glycerol respectively, including cetane number (56—53), heat of combustion (37—39 kJ/g), oxidative stability (8.58 h), kinematic viscosity (3.82—3.79 mm /s), density (807—872 kg/m ), and iodine index (74—115.5 gE/lOOg). Leiva-Candia et al. (2015) estimated biodiesel properties produced from SCO derived from Rhodosporidium toruloides, Lipomyces starkey, and Cryptococcus curvatus cultivated on biodiesel by-product streams. More specifically, cetane number (62.39—69.74), lower calorific value (37,393.49—37,561.68 kJ/kg), cold-filter plugging point (4.29—9.58°C), flash point (158.73—170.34°C), and kinematic viscosity (4.6—34.87 mm /sat 40°C) were determined. 

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