Biodiesel properties

Contrary to what is seen with vegetable oils, biodiesel produced from animal fats has component units that are dominated by saturated alkyl species, and the observed biodiesel properties reflect the presence of these species. The fuel is more stable and degrades less in the presence of air. However, cloud-points and pour-points are higher, meaning that it may show poor performance at cold temperatures. 

Ramos, M. J., C. M. Eernandez, A. Casas, L. Rodriguez, and A. Perez. 2009. Influence of Patty Acid Composition of Raw Materials on Biodiesel Properties. Bioresource Technology 100 (l) 261-268. 

Fatty acid stmcture (composition and imsaturation degree) of vegetable oils used as feedstocks considerably affect the physical properties of biodiesel such as viscosity, cold flow properties, oxidation stability and exhaust emission profile (Knothe 2008). Even, there are many successful attempts to predict the biodiesel properties from the fatty acid composition of the plant oils. Fatty acid distribution of some common vegetable oils is given in Table 2. Higher saturated fatty acid based biodiesel has higher viscosity, cold flow temperatures, oxidation stability and calorific value while higher imsaturated fatty acid based biodiesel shows a combination of improved fuel properties as a whole (Knothe 2005 Ramos 2009 Kumar 2013). 

Ramos, J. M., Fernandez, C. M., Casa, A., Rodriguez, L. and Perez, A. (2009). Influence of fatty acid composition of raw materials on biodiesel properties. Bioresource Technology. 100, 261-268. 

The same model compression ignition engines/vehicles emissions of biodiesel are presented in Table 3.5. NO emissions enhance with respect to increasing biodiesel amounts in the blends. In general, there are various similarities in the petroleum diesel and biodiesel properties. Therefore biodiesel is an excellent alternative to diesel and is rated as a realistic fuel. In addition, NO emissions increase with respect to the high length of the combustion period, combustion temperature, and the availability of biodiesel (Demirbas, 2010). 

INTEGRATED BIOREFINERY OE BIOETHANOL AND PLATEORM CHEMICALS TABLE 22.2 Comparison of Biodiesel Properties (Bharathiraja et al., 2014)... 

Several authors have explored the potential of Annona oil for second-generation biodiesel (AOBD) production as its low acid value and fatty acid profile (rich in oleic and palmitic acids) bestows excellent properties on AOBD, meeting the international standards ASTM D6751 (Reyes-Trejo et al., 2014) and EN14214 (Branco et al., 2010). Characterization of several Annona species showed different yields and fatty acid profiles as Table 5.5 depicts. The greatest differences have been found for palmitic acid (C16 0), oleic acid (C18 l), and Unoleic acid (C18 2), therefore affecting biodiesel properties from different Annona species. 

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. 

The characteristics of fatty acids of biodiesel feedstock are of great importance because they determine, to a great extent, the key properties of biodiesel. Properties like viscosity, cold flow, and oxidative stability depend heavily on the composition and stmcture of fatty acyl esters (Knothe, 2005). Fatty acids are either in saturated or unsaturated form, of which the unsaturated fatty acids may vary in the nmnber and position of... 

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. 

The first engines invented by Rudolf Diesel ran on groundnut oil, but because of the advent of relatively cheap oil this type of biodiesel never became commercially viable. Since about 1930 the diesel engine has been refined and fine tuned to run on the diesel fraction of crude oil, which consists mainly of saturated hydrocarbons. For this reason the modem diesel engine cannot run satisfactorily on a pure vegetable oil feedstock because of problems of high viscosity, deposit formation in the injection system and poor cold-start properties. Today, however, environmental... 

This prompted us to investigate the possibility of selectively hydrogenate highly unsaturated oils, unsuitable for the production of Biodiesel, in order to improve their oxidative stability while keeping the cold properties. 

Hydrotreating has been proposed by Arbokem Inc. in Canada as a means of converting Grade Tall Oil into biofuels and fuel additives. However, this process is a hydrogenation process which produces hydrocarbons rather than biodiesel. Recently a process for making biodiesel from crude tall oil has been proposed. It relies on the use of an acid catalysts or of an acyl halide for the esterification reaction, but no information is given on the properties of this fuel, particularly concerning the oxidative stability. 

During the last decade many industrial processes shifted towards using solid acid catalysts (6). In contrast to liquid acids that possess well-defined acid properties, solid acids contain a variety of acid sites (7). Sohd acids are easily separated from the biodiesel product they need less equipment maintenance and form no polluting by-products. Therefore, to solve the problems associated with liquid catalysts, we propose their replacement with solid acids and develop a sustainable esterification process based on catalytic reactive distillation (8). The alternative of using solid acid catalysts in a reactive distillation process reduces the energy consumption and manufacturing pollution (i.e., less separation steps, no waste/salt streams). 

Table 10.2 Properties of ethers blended in diesel and in mixtures of biodiesel and diesel.

Table 4.6 Typieal properties of petroleum and biorenewable feedstocks and biodiesel...

Table 4.7 Fuel properties of diesel, biodiesel and biomass pyrolysis oil...

Property Test method ASTM D975 (diesel) ASTM D6751 (biodiesel, BlOO) Pyrolysis oil (bio-oil)... 

Table 10.1 Physical-chemical properties of diesel compared with biodiesel.

Much work has been done on the incorporation of castor oil into polyurethane formulations, including flexible foams [64], rigid foams [65], and elastomers [66]. Castor oil derivatives have also been investigated, by the isolation of methyl ricinoleate from castor oil, in a fashion similar to that used for the preparation of biodiesel. The methyl ricinoleate is then transesterified to a synthetic triol, and the chain simultaneously extended by homo-polymerization to provide polyols of 1,000, 000 molecular weight. Polyurethane elastomers were then prepared by reaction with MDl. It was determined that lower hardness and tensile/elongation properties could be related to the formation of cyclization products that are common to polyester polyols, or could be due to monomer dehydration, which is a known side reaction of ricinoleic acid [67]. Both side reactions limit the growth of polyol molecular weight. 

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. 

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