XII Международная студенческая научная конференция Студенческий научный форум - 2020

Biodiesel is the most well-known biofuel in this country. Around 1.8 m. tonnes of bio­diesel from vegetable oils are consumed in Germany each year. This corresponds to roughly two-thirds of German biofuel sales.

Raw materials

For many people, ‘biodiesel’ calls to mind blossoming fields of rapeseed, and in Ger­many it is indeed primarily sourced from rapeseed. However, other vegetable oils and also used edible fats and animal fats can serve as possible alternative starting materials.

Whereas, for climatic reasons, in Central Europe it is rapeseed that dominates in the production of biodiesel, in Asia it is normal­ly manufactured from palm oil and in Amer­ica from soya oil. Biodiesel sourced from recycled materials is also gaining in significance. Compared to biodiesel obtained from cultivated biomass, it is primarily the lower GHG emissions that are stated as an advantage of biodiesel sourced from used edible fats.

In this country, biodiesel is mostly obtained from rapeseed, as a native raw material. The cultivated area, almost constant in recent years at around 1.4 m. ha, lends emphasis to the great significance of rapeseed culti­vation in Germany. Manufacture of edible oil, margarine, etc. requires a rapeseed culti­vated area of around 300,000 ha. Industry accounts for around 120,000 ha, using the product as a material. Yet the lion’s share that remains, around two-thirds of domes­tic rapeseed area cultivated, is available to biofuel production and, where applicable, to export.

For a chemist, biodiesel is in fact vegetable-oil methyl ester, or respectively it is charac­terised as fatty acid methyl ester (FAME). The abbreviation RME is also established for rapeseed-oil methyl ester. Thus biodiesel is not to be confused with vegetable oil but is manufactured from it.

Manufacture

In Germany the first facilities for biodiesel production were set up in the 1990’s. It is manufactured by transesterification of vegetable oil with methanol: for this, veg-etable oil is mixed with methanol in a 9:1 ratio. To accelerate the process, 0.5–1 % of a catalyst (sodium hydroxide or potas-sium hydroxide) is added and the mixture is stirred at temperatures of 50–80 °C for several hours. In the chemical reaction that follows, the vegetable-oil molecule, consisting of glycerine and three fatty-acid chains, is split. The trivalent alcohol, glycer-ine, is replaced by the monovalent alcohol, methanol, so that the fatty acids combine with methanol to form biodiesel. What re­mains at the end of the reaction is raw bio­diesel and raw glycerine in two easily-sepa­rable phases.

So as to attain biodiesel of the desired prod­uct quality, raw biodiesel must go through several steps of processing. The same ap­plies to the glycerine, an alcohol that finds use in many business sectors, such as phar­maceuticals, the food industry and the oil sector, and is normally manufactured syn­thetically .

Development of Biodiesel. Production and sales in Germania .

Properties and quality of the fuel

For the use of vegetable-oil fuels, the engine needs to be adapted to the fuel; in the case of transesterification to form biodiesel, the fuel is adapted to suit the engine. As regards viscosity and its ignition performance, it has similar characteristics to fossil-based diesel. Through using additives, as is also custom­ary for traditional fuel, the product is made suitable for winter use: as low as –20 °C, biodiesel can be used without problems. The lubricity of biodiesel, important to keep wear-and-tear on the engine low, is even higher than that of fossil fuel. By contrast, the energy content per litre is somewhat lower; this can lead to additional consump­tion of up to 5 %.

Im 2003 the requirements necessary for fuel quality were established in the DIN EN 14214 norm, valid throughout Europe. The integra­tion of the latter into the 10th Federal Immis­sion Protection Ordinance (10. BImSchV) also anchors these requirements in national law. If biodiesel is offered at public fuel-stations, it is obligatory to make known the quality of the fuel, according to the norm, by attaching the DIN sticker to the fuel-pump column.

The oil companies add up to 7 % biodiesel (B7) to traditional diesel, without any need for the vehicle-holder to take any technical prerequisites into account. To comply with the norm for fossil-based diesel fuel (DIN EN 590), the mineral-oil manufacturers may only add biodiesel that in turn corresponds to the biodiesel norm DIN EN 14214. On the fuel-pump column, a sticker stating “Con­tains up to 7 % biodiesel” directs attention to the so-called B 7-fuel.

As is customary for petrol and diesel, ad­ditives are also put into the biodiesel in order to improve its properties. Informa­tion on quality-assurance with regard to biodiesel is offered by the Association Quality Management Biodiesel e. V. at www.agqm-biodiesel.de an .

APPROVALS FOR BIODIESEL VEHICLES

For use of biodiesel as a pure fuel or in mixtures with a biodiesel proportion of > 7 %, approval by the manufacturers is necessary. In non-approved vehicles, biodiesel’s prop­erties, similar to those of solvents, can lead to problems; where applicable, the product can attack plastic and rubber components, such as seals and petrol-ducts in the engine. Overviews with regard to vehicle approvals for biodiesel (B 100) in agricultural and for­estry use, but also for the commercial-vehicles sector more broadly (B 100 and B 30), can be accessed on the internet pages of the Union for the Promotion of Oil and Protein Plants (abbreviation: UFOP)) at www.ufop.de. Likewise, when retrofitting particle filters it is essential to ensure that the filter and vehicle are approved for biodiesel use .

Biodisel sales in Germany .

Market presence/use

Supported by complete tax-exemption, the history of biodiesel in Germany began with the sale of pure fuels – also known as B 100. Vehicle fleets tanked up their commercial ve­hicles with biodiesel and numerous car mod­els obtained approvals for use of this fuel. The biodiesel market in Germany changed with the stage-by-stage introduction of tax from mid- 2006 and with the biofuel quota, created as a countervailing measure. Higher raw-material prices and increasingly demanding require­ments regarding emissions adversely affected sales of B 100, such that today biodiesel as a pure fuel comprises less than 1 % (around 3,000 t) of total biodiesel sales – more than 99 % of the total consumed is added directly to diesel fuel by the oil companies.

At 3 m. tonnes, biodiesel production ex­ceeded domestic sales of 1.8 m. tonnes in 2015. In this context the manufacturers in this country – with a production capacity of 4 m. tonnes in all – primarily use native raw materials. Accordingly, in Germany in 2015 around 650,000 ha of rapeseed were used for the production of biodiesel and vegeta­ble oil .

Environmental aspects

Through the use of 1.8 m. tonnes (t) of biodiesel in Germany in 2015, more than 1.8 bn. litres of diesel fuel were replaced and around 2.1 m. t of greenhouse-gases saved. Thus biodiesel’s contribution to the protec­tion of resources and of the environment is undisputed. That contribution will further in­ crease because it is to be expected that the latest requirements of the sustainability or­dinance (among other things) will generate further optimisations in biofuel production.

The production of biofuel causes emissions, along the chain of manufacture and supply, that are primarily to be attributed to the ac­tivity areas of cultivation and processing. The latest targets stipulate a GHG saving of 35 % in relation to a reference value for fossil-based diesel fuel; from 2018 the rel­evant value is raised to 50 %. How many GHG emissions the biodiesel saves in the individual case can be calculated for one particular facility or via the standard values from the “EU Directive on the Promotion of Energy from Renewable Sources”. Accord­ing to this, biodiesel made from rapeseed saves at least 38 % of GHG compared to the reference fuel; biodiesel from sunflowers even saves 51 %.

It is the cultivation of biomass, above all, that provides potential for savings. Thus an optimised deployment of fertiliser and the taking into account of average rapeseed yields (that are by now further increased) positively affected the GHG balance. The DBFZ calculates that, in practice, the emis­sions in the case of biodiesel sourced from rapeseed could therefore be roughly one third below the conservative EU standard value [5].

GHG EMISSIONS: BIODIESEL FROM RAPESEED .