Biodiesel standards

Technical background of critical items in the biodiesel standard 86... 

These different businesses may have diverse backgrounds, rooted in vegetable oil business or the petrol business, or based on investment financing, however, they all have one thing in common they produce biodiesel, or better fatty acid methyl esters (FAME) to be used by petrol companies for blending with fossil diesel to B2, B5, B10 or B100. These fatty acid methyl esters must comply with the Biodiesel Standard in use in the region of commercialization. And most importantly, this biodiesel needs to be produced at a market competitive price. 

Without the Biodiesel Standard, there would be no sustainable biodiesel market. The Biodiesel Standard guarantees that products are properly tested for blend properties, performance in engine use, and functionality with injection systems used in the modern common rail diesel engines. Many car manufacturers state that FAME used in commercial fuel must meet both standard references EN14214, the European Biodiesel Standard, and ASTM D 6751, the U. S. Biodiesel Standard (Table 3.1). Making biodiesel that complies with the applicable Biodiesel Standard helps guarantee the functionality and performance in transport engines. 

Let s have a look at these specifications and evaluate how they relate to functionality. We can then assess how they can be related to FAME composition, and how they could be used to calculate the Lowest Cost Blend of FAME, while still complying with the requirements of the applicable Biodiesel Standard. 

TECHNICAL BACKGROUND OF CRITICAL ITEMS IN THE BIODIESEL STANDARD... 

Fuel density is important for blending characteristics, but also relates to emission levels, fuel consumption, and emission control systems. Similarly, the viscosity of the fuel is important. Kinematic Viscosity is included in the Biodiesel Standard because it relates directly to the injection system performance. In the Biodiesel Standards, viscosity is often set at a specific temperature point. With most fatty acid methyl esters this is never a problem, but viscosity changes at low temperature can be much more problematic. Biodiesel tends to thicken faster than fossil diesel. Specific additives might be required to deal with this. 

In the different Biodiesel Standards the specifications are linked to the fatty acid composition itself. Some characteristics may be affected by the presence of minor components, but most variation is directly linked to the FAME composition. Two questions emerge how are these relationships built, and how can we take advantage of these when making blends with the lowest possible raw material price ... 

The Biodiesel Cost Optimizer (Fig. 3.2), built as a mathematical tool, has been developed to help the biodiesel industry find a least cost formula for making FAME compositions that perform within the specifications of the applicable Biodiesel Standard. The Excel Workbook Biodiesel Cost Optimizer contains three separate sheets ... 

With an easy click the Biodiesel Cost Optimizer can select for European Biodiesel Standard EN 14214, or U. S. Biodiesel Standard ASTM D 6751. If needed other target values can be input manually. 

Standard canola oil, mainly because of its fatty acid composition, is relatively well suited for biodiesel production. Harrington (145), and Knothe et al. (146) discussed desired properties of fatty acid ester structure for biodiesel. Knothe et al. (146) also discussed biodiesel standards in different countries, for those interested. Briefly, the desired properties of vegetable oil fatty acids for methyl ester biodiesel can be summarized as follows ... 

The desired properties of methyl esters for biodiesel are given in Table 24 (147). These properties are the German biodiesel standard Deutsche Industrie Norm (DIN) V 511605. This standard, as well as other European standards, was developed, especially with canola/rapeseed oil as the starting material in mind. The suggested... 

Most biodiesel synthesis processes produce a fuel that has a slight contamination with acylglycerols, and this fact is recognized in most current biodiesel standards (Table 1). In spite of their low concentrations, these acylglycerols may contribute disproportionately to fuel lubricity. 

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. ... 

Biodiesel standards have been or are being developed in many countries or regions around the world. The American biodiesel standard ASTM D6751 and the European biodiesel standard EN 14214 are standards that have been utilized by other countries when developing their own standards. The current versions of ASTM D6751 and EN 14214 are summarized in Table 16.2. 

Table 16.2., cont. Biodiesel Standards ASTM D6751 and EN 14214... 

Knothe, G. Analyzing biodiesel standards and other methods. J. Am. Oil Chem. Soc. 2006b, 83, 823-833. 

In the modern 00-rape the > C 20 fatty acids have been reduced to trace fractions in favour of oleic, linoleic and linolenic acids, resulting in a fatty acids spectrum similar to olive oil. Characteristics of 00-rape are the most appropriate to fulfil the European biodiesel standards. As a result, the EU-27 are now the by far largest rapeseed oil consumers, and the astounding growth in European demand has been driven almost exclusively by the expansion of the biofuels sector over recent years. Fifty percent of European rapeseed production in 2005 has been turned into biodiesel, 37% has been used for human consumption, 7% for oleochemical products and lubricants 6% has been exported. In 2007 the rape oil demand for biofuels has accounted for 60% of rape oil consumption. Rape-based biofuels include biodiesel and direct use as refined oil. 

Y. M. Choo, C. W. Puah and M. Basri Wahid, Outlook of Palm Biodiesel in Malaysia, Malaysian Palm Oil Board, 2007 Y. M. Choo, H. L. N. Lau and C. L. Yung, Biodiesel Standard Development in Malaysia Impacts of Palm Biodiesel on Engines and Emissions, www.tistr.or.th/APEC website/ APEC pdfs/A-9 Dr.%20Choo Bangkok APEC%20-%2025%200ct% 202007.pdf (retrieved 14.05.2008). 

The major biodiesel standards are ASTM D 6751 [669] and the European EN 14214 [670] standard, whose requirements are somewhat equivalent At present D 6751 applies to BlOO biodiesel that is used for blending. Among the many parameters controlled by this standard are the concentrations of sodium, potassium, magnesium, and calcium in biodiesel. Alkali and alkaline-earth metals in the fuel can form ash and soaps, which may cause detrimental deposits in engines. To prevent engine damage firom the blended fuels, these cations are limited to a cumulative concentration of less than 5 mg/L for the alkali metals sodium and potassium and for the alkaline-earth metals magnesium and calcium. 

Properties Algal Biodiesel Petro Diesel American Standards for Testing Materials (ASTM) Biodiesel Standard... 

The properties of a biodiesel fuel that are determined by the structure of its component fatty esters include ignition quality, cold flow, oxidative stability, viscosity, and lubricity. The present work discusses the influence of the structure of fatty esters on these properties. Not all of these properties have been included in biodiesel standards, although all of them are essential to the proper functioning of the fuel. This article begins, however, with brief summaries on the historical background, production, and analysis of biodiesel. 

TABLE 2.2 Fuel Property Specifications in Biodiesel Standards... 

Induction times determined for neat fatty acid esters using the Rancimat method are also given in Tables 2.3 and 2.4. It may be noted that no unsaturated fatty ester has an induction time >3 h, which is the minimum specification in the ASTM biodiesel standard. This observation implies that antioxidant additives will almost always be necessary to attain the minimum oxidative stability specification in biodiesel standards. 

---