Biofuels
Increasing globalisation means that now, more than ever, mobility is the key to positive economic development. However, this constantly growing global need for individual mobility has led to ever-increasing energy consumption within the transport sector, which in Germany has been more than 90 % dependent on oil up to now. Due to the finite availability of oil and its rising price, a growing number of countries have begun to gradually increase the percentage of biofuels in their fuel supply policies. The biofuel market is currently dominated by biodiesel and bioethanol, with bioethanol definitely having the greater global importance. German companies offer many years of proven and reliable system technology for raw material processing (oil mills) and for the production of biofuels. They cover all aspects of the value chain and construct systems around the world for the production of biodiesel, bioethanol and biogas, which canbe processed to natural gas quality.
Technologies and applications
Bioethanol
Bioethanol is manufactured from various agricultural feedstocks containing sugar and starch. In Europe, cereals and sugar beet are used, while sugar cane is used in Brazil and maize in the USA. As with conventional alcohol, bioethanol is produced by fermenting sugars using yeasts, followed by a purification process. If cereals are used, the starches are first enzymatically converted into sugars. This creates a by-product known as dried distillers grains with solubles (DDGS). With a protein content of 30 %, DDGS is a valuable, high-protein animal feed.
The fermentation of distillers grains and other residues of bioethanol production in biogas plants presents another interesting opportunity for energy recovery. The resulting biogas remains as process heat in the plant or is fed into the grid. By-products resulting from the manufacture of bioethanol from sugar beets are vinasse and sugar beet pulp, which are used as animal feed or fertiliser. Every litre of bioethanol produced results in one kilogram of DDGS or 600 g of vinasse and beet pulp.In Germany, bioethanol is primarily used in differing concentrations in petrol. The regulatory framework for a national allowance of up to 10 % by vol. bioethanol petrol (E10), replacing the previous maximum of 5 % (E5), was laid down in the 2009/30/EC directive. Since the beginning of 2011, E10 has been available at German petrol stations. Over 90 % of all passenger cars in Germany and, in general, all new cars can easily fill up with E10.
All petrol stations throughout Germany are required to offer conventional petrol (E5) as fuel for the time being. E85 bioethanol fuel is available at approx. 350 filling stations across Germany. E85 has a particularly advantageous carbon footprint: From field to tank, E85 creates only around half as much CO2 as petrol from fossil fuels. Appropriately converted vehicles, so-called flexible fuel vehicles (FFVs), can be operated with varying percentages of bioethanol of up to 85 % (E85). FFVs are “fuel flexible”: A sensor recognises the petrol-bioethanol mix ratio in the tank and automatically adjusts the motor to the correct ignition timing for the mixture’s composition. On the German market, Audi, Bentley, Ford, Opel, Saab and Volvo offer FFVs.
Another important market for bioethanol is in the manufacture of ethyl tertiary butyl ether (ETBE), which has a bioethanol content of 47 %. ETBE can be used as a replacement for methyl tertiary butyl ether (MTBE), which is manufactured exclusively from fossil fuels and used as an additive to prevent knocking in petrol engines. The EU Fuel Quality Directive stipulates that petrol may contain up to 22 % ETBE.According to estimates, the global production of bioethanol in 2010 increased to just over 70 million tonnes (from 60 million tonnes in 2009). EU production in 2010 rose to around 3.5 million tonnes (from just under 3 million tonnes in 2009). Production at the nine bioethanol plants in Germany remained virtually unchanged in 2010 in comparison with the previous year, with almost 0.6 million tonnes produced. Beet stock accounted for a third of production, while two-thirds of German bioethanol was extracted from grains.
The most important grains for bioethanol production are wheat and rye; with oats, barley, maize and triticale also playing a part. The use of bioethanol has once again exhibited strong growth, with consumption standing at 1.6 million tonnes – 28 % higher than in 2009 (0.9 million tonnes). This had a knock-on effect of increasing the volumetric percentage of ethanol in total petrol consumption from 4.5 % in 2009 to 5.9 %.
PPM Energie Germany GmbH
This biodiesel production plant in Regensburg, Germany, produces around 33,000 tonnes of biodiesel annually from fresh and used plant oils as well as from animal oils. The by-product crude glycerine is utilised in the biogas plant as a co-substrate.
Biodiesel
Vegetable oil is the base ingredient from which biodiesel is produced. In principle, any vegetable oil can be used, with rapeseed being the primary source material in Europe and soya oil in South America and the USA. Palm oil, sunflower oil and jatropha oil can also be used. After appropriate processing, used cooking oils and animal fats can also be used to produce biodiesel. However, plant oils vary in their fatty acid composition and thereby in their suitability, also in winter months, for use in the form of biodiesel.
This attribute is known as the CFPP value (cold filter plugging point), which is plus 5 for palm oil and minus 12 degrees for biodiesel from rapeseed. From the CFPP value, biodiesel usage can be restricted to a limited time frame (e.g. summer) according to the climate, during which time biodiesel from palm oil can be mixed with conventional biodiesel.
During the extraction of vegetable oils, rape or soya grist is produced as a by-product. Either of these can be used as a high-protein feed for livestock. Every 100 kg of rapeseed produces roughly 57 kg of rape grist and 43 kg of rapeseed oil, while 100 kg of soybeans produce around 80 kg of grist and 20 kg of oil. Depending on the specific plant technology, de-gummed or additionally extracted or refined oil is transesterified into fatty acid methyl ester (FAME/biodiesel) by adding methanol and a catalyst. Separate markets exist for glycerine, a by-product created during transesterfication, primarily in the pharmaceutical industry. The process results in a fuel similar in both the energy density and, most importantly, the viscosity of regular diesel, which means it can be used in conventional diesel engines.
In recent years, the process for manufacturing biodiesel (“fatty acid methyl ester” or FAME) has been continuously refined in Germany. At present, German companies market systems for the large-scale production of several hundred thousand tonnes per year as well as for smaller, decentralised systems with an annual capacity of several thousand tonnes. Over the past 10 years, a consortium of German biodiesel producers and dealers has developed a quality management system that currently supports plant operators at home and abroad with its “Biodiesel Production AGQM Certified” programme (BPAC). The basis for BPAC certification is compliance with limits set out in DIN EN 14214 and supplemented by additional requirements for certain test parameters. BPAC also takes into account the various regional specifications of the German market.
In its undiluted form (B100), biodiesel can be used as a fuel in commercial vehicles (HGVs, buses and agricultural vehicles). It can also be mixed with conventional diesel. Since the end of 2010, diesel mixtures containing up to 7 % by vol. biodiesel can be sold in Europe on the basis of the amended European standard for diesel – EN 590. Global production of biodiesel in 2010 was estimated at some 18 million tonnes (2009: 14 million tonnes), of which 26 % was produced in South America (Brazil and Argentina), 13 % in the USA and approx. 61 % in the 27 EU Member States. In Germany, production capacity in 2010 was approx. 4.9 million tonnes (45 plants with individual capacities between 2,000 and 580,000 tonnes per year), making it the world’s top producer. In 2010, 2.6 million tonnes of the diesel fuel substitute biodiesel was consumed in Germany – equivalent to 8 % of Germany’s diesel fuel consumption. Untreated vegetable oils can also be used as a fuel in diesel engines for mobile and stationary applications (combined heat and power plants). However, due to the higher viscosity and lower cetane number of vegetable oil fuel in comparison with diesel fuels, the engines must undergo minor modifications. Conversion kits for carrying out the modifications are available from German companies in the form of pre-fabricated modules, which can be integrated easily into existing fuel supply systems (one- or two-tank systems). Sales of vegetable oil fuel in Germany totalled 60,000 tonnes in 2010.
Biomethane
Biogas purified to natural gas quality (biomethane) can be used without modification as a fuel in natural gas vehicles. Produced by anaerobic fermentation, biogas is refined through the removal of carbon dioxide and other trace gases until it corresponds to the quality of fossil natural gas. The biomethane can then be fed into the natural gas grid or obtained at any natural gas filling station. Once it has been compressed to 250 bar, it can also be used directly as a fuel. A biogas filling station can be located adjacent to a biogas plant equipped with the required processing system. In this way, vehicles powered by natural gas can be supplied via an off-grid system. At the end of 2010, the number of natural gas vehicles worldwide stood at around 12.7 million, an increase of some 12 % over the previous year. Of this number, Pakistan alone has around 2.74 million, Iran 1.95 million, Argentina 1.9 million and Brazil 1.66 million. Italy is the leader in Europe with approx. 730,000 vehicles. Some 92,000 vehicles are powered by natural gas in Germany. Over 18,000 natural gas stations are in operation worldwide.
