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FAME, Fatty acid methyl esters CH3(CH2)nCOOCH3
Fatty acid methyl esters, FAME, is a nontoxic bio-degradable biodiesel. FAME can be produced from many different vegetable oils, e.g rapeseed, sunflower, soy and palm oil. Animal fats and recycled cooking oil from restaurants can also be used. The most common biodiesel today on the Swedish market is rapeseed methyl ester (RME).
Primary area of use
Fatty acid methyl ester, FAME, is used as a fuel in vehicles for road transport. The common name is biodiesel. FAME is fully miscible with fossil diesel and is used in different blends with fossil diesel. FAME as a low blend component in diesel (up to 7% in Europe, limited by the EU Fuel Quality Directive) requires no changes in distribution system and vehicles. FAME can also be used as a pure fuel, and is then called B100. However, since the use of B100 may require engine modifications and adjustments, it is mainly used in heavy trucks.
Feedstock and production
FAME can be produced from a wide array of oils and fats. The most common feedstock in Europe is rapeseed and sunflower. In USA, soybean oil is typically used, while palm oil is used in Asia. FAME can also be produced from corn, algae, jatropha, animal fats and waste vegetable oils. The feedstock used determines the properties of the product due to the differences in the chemical composition of fatty acids.
A vegetable oil is a triglyceride, which chemically can be described as three fatty acids linked to glycerol. The triglyceride in the oil separates to form FAME and glycerin through transesterification, a process where the glycerol in the oil is replaced with an alcohol, usually methanol, under the action of a catalyst (e.g. sodium hydroxide). Today, the methanol is typically of fossil origin, but can also be produced from renewable raw materials. Glycerol is a byproduct from this process.
In Sweden, the main type of FAME is RME, produced from rapeseed oil. RME production consists of two processes: oil extraction from rapeseed followed by conversion of the oil to RME by transesterification. In the latter step, the rapeseed oil is heated before it is mixed with the base catalyst and methanol. The triglycerides in the rapeseed oil react with the methanol to form a straight-chain diesel fuel. The RME is then separated by distillation and washed.
The transesterification reaction for producing FAME from a vegetable oil.
In 2013, 293 000 m³ of FAME were consumed in Sweden. Of this 240 000 m³ was sold in low blends and 42 000 m³ was sold as pure FAME, B100. To fulfil the demand of the Swedish market, FAME is also imported. The amount of FAME imported has increased during the last three years. FAME is mainly imported from Lithuania, Germany, the Netherlands, Denmark, Norway and Italy. Svenska Petroleum och Biodrivmedels Institutet, SPBI, has reported that low blend diesel with FAME represented 2,7 % of the the total use of fuel in the Swedish transport sector in 2012 (on energy basis). The corresponding figure for pure FAME, B100, is 0,4 %.
The largest producer of FAME/biodiesel globally is USA with a production of roughly 5 billion liters in 2013, followed by Germany, Brazil and Argentina.
According to the EU Fuel Quality Directive, the maximum blend of FAME into ordinary market diesel is 7%. The EU Renewable Energy Directive allows higher blending levels in diesel. Low blends do not require any modifications in the distribution systems. The transport of FAME and diesel blends can therefore use liquid-product pipelines and the existing distribution systems for fossil diesel. The diesel distributed today at filling stations in Sweden contains roughly 5-7% FAME, depending upon seasonal and geographical conditions. The distribution of pure FAME, B100, is primarily limited to direct deliveries to customers.
There are two main production sites in Sweden; Perstorp in Stenungsund, producing roughly 130 000 m³ RME per year, and Energigårdarna in Karlshamn with a production capacity of 14 000 m³ RME per year. There are also many small Swedish production sites, for example Tolefors Gård in Östergötland which produces roughly 400 m³ RME per year from used cooking oil.
Caps on first generation biofuels in USA and Europe, the strong position of Hydrotreated Vegetable Oils and the possible of removal of tax incentives in Sweden in the past years have raised many concerns in the FAME/biodiesel community. Nonetheless, the development of biodiesel continues, and new production plants are being built worldwide. Large plants for biodiesel production from used cooking oil have been established in the Netherlands and Portugal. There are also many new projects in USA developed for vegetable oils and waste oils. France, the largest consumer of biodiesel in Europe, wants to increase biodiesel use even more, and will include 7.7% biodiesel in all diesel fuel in the coming years. Furthermore, an increased interest in using algae to produce biodiesel has been seen in the biofuel and research communities.
Chemical formula: CH3(CH2)nCOOCH3 (General formula, European Biofuels Technology Platform)
Molecular mass: RME: 296g/mol (Oleic acid C18:1)
Density at 15°C 1,013 bar: 860-900 kg/m³ (EN 14214)
Heating value: RME: 38 MJ/kg (European Biofuels Technology Platform)
Cetane number < 51