Biodiesel heating value

Biodiesel (fatty acid methyl esters) is an alternative and renewable energy source, the development of which is hoped to reduce global dependence on petroleum, as well as air pollution. Biodiesel generated Ifom a variety of vegetable oils and animal fats has characteristics similar to those associated with petro-diesel, including viscosity, volumetric heating value, cetane number, and flash point [1-3]. Several processes have thus far been developed for the production of biodiesel via acid-, alkali-, and enzyme-catalyzed... 

A new development in the area of alternative diesel fuels is a fuel produced from vegetable oils and animal fats using specially modified hydrogenation processes in a conventional petroleum processing facility (Rantanen et al., 2005). This fuel retains the low sulfur and low aromatic character of biodiesel but contains no oxygen and has a heating value that is similar to petroleum diesel fuel. Recent U.S. interest in this approach has expanded due to governmental announcements that the fuel qualifies for federal excise tax credits. 

Fassinou, W. R, A. Sako, A. Fofana, K. B. Kona, and S. Toure. 2010. Fatty Acids Composition as a Means to Estimate the High Heating Value (HHV) of Vegetable Oils and Biodiesel Fuels. Energy 35 (12) 4949-4954. 

Similarly to biobutanol, biopropanol is another bioalcohol with high heating value. Isopropanol can be dehydrated to produce propylene, a product that can be used to esterify fats and oils for the production of biodiesel. Isopropanol can be produced by Clostridium or genetically modihed E. coli. Commercial isopropanol production from biomass-derived glucose is highly desired (Ismaiel et ah, 1993). However, the highest concentration of biopropanol observed from fermentation experiments was 4.9 g/L (Atsumi and Liao, 2008), which is still much lower than the titer of the bioethanol production process. More research would be expected to increase the efficiency and yield of the process before sizable application. 

The energy balance for the production of an alternative fuel can be enhanced if the byproducts are used to produce some of the energy required to produce the fuel. For example, if the soybean meal or the glycerin were burned to provide process heat for the conversion of soybean oil to biodiesel, this would improve the overall energy balance. Currently, the economic value of these byproducts is higher for use as animal feed and other products than for use as fuel. 

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.

The work herein has shown the suitability of P-DSC as an accelerated oxidation stability test method for biodiesel. Different biodiesel blends (B7) were compared in terms of their oxidative stability by P-DSC using dynamic (linear heating up to oxidation) and isothermal modes (maintaining constant temperature at a fixed value up to oxidation). The OOT and OIT parameters were determined for each studied blend and the positive influence of chain-breaking type additives (such as amine and/or phenolic compounds) has been shown. BHT showed better results (high OOT and OIT values) than TBHQ, but EAP, which is a mixture of 1 amine and 2 phenolic compounds, was by far the best AO. Synergetic effects could explain these very good results. 

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. 

---