Biodiesel (FAME)

What is biodiesel (FAME)?

Biodiesel is one of the biofuels and is a biofuel produced by transesterification from vegetable oil, also known as fatty acid methyl ester or FAME. Biodiesel is generally suitable for use in diesel engines.

How is biodiesel produced?

In Europe, biodiesel is mainly produced by transesterifying rapeseed oil with methanol, which is why biodiesel is also known as rapeseed oil methyl ester (RME). Fatty acid methyl ester, which is produced from recycled fats or oils, is sometimes abbreviated to AME. In principle, a wide variety of fats can be used to produce FAME, but in practice, limit values for some parameters such as cold properties, oxidation stability and coke residue restrict the possible range of raw materials.

The production of biodiesel is associated with high technical and energy costs. Methanol is required, which has generally come from fossil sources, at least until now; however, methanol from biomass could also be used in the future. There is a credit in the energy balance for the resulting by-product glycerine, because if the glycerine is used as a material, it does not have to be produced elsewhere.

What are the properties of biodiesel?

Biodiesel has a significantly lower viscosity than untreated vegetable oil, which makes it easier to use. The oil and fat molecules naturally contained in vegetable oil are fatty acids. During transesterification, the vegetable oil is reacted with around 10% methanol by volume. In addition, a catalyst (for example sodium or potassium hydroxide) is added at a temperature of 50°C to 80°C. The amount of catalyst required is 0.5% to 1% by volume of the amount of oil used.

As with conventional fuels, additives are also added to biodiesel to make it suitable for winter use, for example.

The lubricity of biodiesel in the engine is higher than that of fossil diesel fuel. This means that the biogenic fuel can reduce wear. The energy content per liter is lower compared to fossil diesel fuel, which can lead to a volumetric increase in consumption of up to 5%.

The fuel quality requirements for biodiesel are set out in the European standard EN 14214. Numerous parameters such as density, viscosity and ignitability as well as, for example, the maximum ash or water content are specified there. In Germany, DIN EN 14214 was enshrined in law by being included in the Fuel Quality Ordinance, the 10th BImSchV.

FAME is similar in its properties to fossil diesel fuel, which is why it is generally suitable for blending. However, pure biodiesel can also be used in diesel vehicles. However, not all vehicles are approved for the use of pure biodiesel because it can attack plastic and rubber components such as seals and fuel lines in the engine. Biodiesel can also attack non-ferrous metals such as copper and brass as well as zinc in the fuel system. Therefore, before filling up with pure biodiesel, every driver should ensure that the vehicle manufacturer has expressly approved it for the vehicle. Information can be found in the operating instructions or obtained from the dealer or manufacturer.

Biodiesel as a pure fuel now only has a shadowy existence in Germany: In 2014, only 4,800 tons of biodiesel were consumed as a pure fuel; diesel consumption, on the other hand, was 36,000,000 tons. This was different at the end of the last decade, when pure biodiesel was subject to a significantly reduced mineral oil tax rate, but this was constantly being adjusted. According to DIN EN 590 for diesel fuel, the addition of biodiesel - in accordance with DIN EN 14214 - is permitted up to a maximum content of 7% by volume (B7). Different legislation in other European countries continues to allow consumption as pure fuel (e.g. Austria) because tax exemptions ensure competitiveness in some cases.

Fuels such as biodiesel are traded via the Mabanaft Group, e.g. Mabanaft Deutschland and Mabanaft Limited, UK. Oiltanking Deutschland is active in tank storage logistics.