Bioethanol is a natural product and is manufactured by the fermentation of plants containing sugar and starch. In our plants we produce bioethanol from renewable raw materials and from raw alcohol of agricultural origin.
Our plant in Zeitz produces bioethanol from wheat, maize, barley or triticale as well as from sugar syrups.
At this plant the production of bioethanol from starch-containing cereals takes place in five steps:
- Milling, i.e. the mechanical crushing of the cereal grains to release the starch components
- Heating and addition of water and enzymes for conversion into fermentable sugar
- Fermentation of the mash using yeast, whereby the sugar is converted into bioethanol and CO2
- Distillation and rectification, i.e. concentration and cleaning the ethanol produced by distillation
- Drying (dehydration) of the bioethanol
Bioethanol can also be produced directly from sugar syrups. This dispenses with steps 1 and 2, which serve to prepare the grain for fermentation.
At the next-generation ethanol plant in Wanze
the renewable ethanol is produced from wheat. However, the production process is a bit different than usual as it incorporates a different energy concept and produces different food and animal feed products:
- The wheat is cleaned and ground in a mill.
- The bran is separated from the wheat grains and is used to generate primary energy in a biomass plant. This makes the site almost self-sufficient in energy. The ashes are used as compost or organic fertilizers for agriculture. The bran- fibres are used in the animal feed industry.
- The next processing step separates the gluten from the rest of the grain. Gluten and the produced Textured Wheat Protein (BeneoPro W-Tex) are valuable proteins for human and animal consumption.
- By adding enzymes, the starch contained in the wheat is converted into fermentable sugar, which can then be fermented into alcohol. Sugar syrups can be fermented directly.
- In the next step, the fermentation process, yeasts convert the sugar into alcohol and CO2. The alcohol-containing mixture that is produced is referred to as "mash".
- Distillation separates the alcohol from the other components of the mash.
- In the rectification process, this alcohol is then cleaned again. The dehydration - also referred to as drying - of the alcohol then removes virtually all the water it contains. The result is renewable ethanol with an extremely high purity of 99.7 vol.-%.
- The other constituents, the so-called "stillage", are thickened and processed into Concentrated Distiller's Solubles (CDS, ProtiWanze®).
- The biogas produced at the site's water treatment plant is used in the biomass boiler and the sludge from the plant is valorised as organic fertiliser for agriculture.
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Fact Sheet bioethanol
Benefits of European bioethanolDownload (PDF, 516.53 KB)
Schematic diagram of production process of bioethanol and DDGS from grains and sugar syrups
Schematic diagram of the production process in BioWanze